ANVILFIELD
Try FieldOS

Electrical field guides

Electrical guides, checklists, and calculators

Voltage drop, PoE, EV feeders, cable pulling, switchgear receiving, grounding, and power QA.

141 field guides13 calculators15 readiness checks32 field toolsJump to electrical tools

Get the printable electrical field-card pack (PDF)

Latest Electrical guides

Field GuideWearable safety technology and sensors field guide for crewsSafety wearables put a sensor on the worker to catch the gas, the fall, the heat, and the lone-worker emergency and call for help fast, but they speed the rescue, they do not replace the controls.Safety WearablesGas DetectionLone Worker 21 min read Field GuideCommercial building energy audit and management field guideStart with the bills and the EUI benchmark, not the walk-through, match the ASHRAE audit level to the decision, rank the fixes by payback, and prove the savings with measurement and verification.Energy AuditASHRAE 211EUI Benchmarking 21 min read Field GuideConstruction surety bonds and bonding capacity field guideA surety bond is not insurance. It is a three-party guarantee where the contractor pays the surety back for any loss. Bonding capacity is earned through the three Cs, and clean financials plus a solid WIP grow the capacity that lets you bid bigger.Surety BondsBonding CapacityMiller Act 21 min read Field GuideConstruction cash flow and WIP management field guideConstruction runs on cash, not paper profit. Read the WIP to catch underbilling and margin fade early, bill early and often, and collect fast, including retainage and change orders.Cash FlowWIP ScheduleOverbilling 21 min read Field GuideCathodic protection and corrosion control field guideHow cathodic protection stops corrosion on buried and submerged metal, why it complements the coating, and how the potential criterion proves it works.Cathodic ProtectionCorrosion ControlNACE AMPP SP0169 21 min read Field GuideVideo surveillance and CCTV system design field guideDesign the camera, resolution, and lens to the scene and the goal in pixels per foot, then size the storage, the network, and the PoE to match.CCTV DesignPixels Per FootIP Cameras 21 min read Field GuideSubcontractor prequalification and bid lists field guide for electrical contractorsKeep a current prequal package ready, hold the EMR and financials a GC wants to see, and run the same screen on your own subs before you award.Subcontractor PrequalificationBid ListsEMR Safety 21 min read Field GuideSolar PV O&M field guide: utility-scale plant maintenance and monitoringMonitor the production, catch the underperformance, recover the soiling and inverter losses, and work the DC side as live whenever the sun is up.Solar O&MPerformance RatioUtility-Scale Solar 21 min read Field GuidePV rapid shutdown field guide: NEC 690.12De-energize the roof array on one action: the inside and outside boundary limits, MLPE, the listed PVRSS, the firefighter-accessible switch, and the commissioning test that proves it drops.Rapid ShutdownNEC 690.12PV Fire Safety 21 min read Field GuidePreconstruction planning and services field guidePrice the design as it develops, check that it can be built, find savings that keep the value, plan the schedule and site, and lock the budget before a shovel hits dirt.PreconstructionValue EngineeringGMP 21 min read Field GuidePPE hazard assessment and selection field guide for crewsWalk the task, find the hazard to each body part, pick certified PPE that fits, and document the assessment that backs every choice.PPE Hazard AssessmentOSHA 1910.132Hierarchy of Controls 21 min read Field GuidePortable generator interlock and backfeed safety field guideIsolate the generator from the utility so it cannot backfeed, pick an interlock or a transfer switch, handle the neutral and GFCI right, and run it outside.Generator InterlockBackfeed SafetyTransfer Switch 21 min read Field GuideCommercial overhead door and dock leveler installation field guideInstall the door balanced with the right operator safeties, set the leveler and seal in the pit, and hook every trailer with a vehicle restraint before a forklift rolls.Overhead DoorsDock LevelersUL 325 21 min read Field GuideOutside plant fiber and FTTH construction field guideLocate before you dig, choose aerial or underground, place water-blocked cable to the NESC, fusion-splice and OTDR-test the fiber, then map the as-built.OSP FiberFTTH811 Locate 21 min read Field GuideMultiwire branch circuits and the shared neutral, done rightTwo or three hots on different phases sharing one neutral. Wired right it saves a conductor. Wired wrong, the neutral overheats, equipment fries, and a worker gets shocked.Multiwire Branch CircuitShared NeutralNEC 210.4 21 min read Field GuideMedium-voltage switchgear maintenance and testing field guideWhy the gear that protects the whole facility fails silently until it fails catastrophically, and the de-energized inspection, electrical tests, and relay testing on a NETA schedule that keep it from getting there.Switchgear MaintenanceNETA MTSProtective Relay Testing 21 min read Field GuideMedium-voltage cable termination and splicing field guideAn MV cable end controls an invisible electric stress field, not just a connection: the stress cone, surgical cleanliness, the kit's exact dimensions, shield grounding, and the VLF or PD test that proves it.Medium VoltageCable TerminationStress Cone 21 min read Field GuideMechanics lien and preliminary notice field guide for getting paidProtect the right to get paid: send the preliminary notice on day one, calendar the hard deadlines, sign waivers carefully, and claim the bond on public jobs.Mechanics LienPreliminary NoticeLien Waivers 21 min read Field GuideJob expense and receipt tracking field guide for electrical contractorsCapture every material buy, PO, fuel charge, rental, and reimbursable against the right job so it gets billed, costed, and deducted instead of lost in the truck.Job ExpensesReceipt CapturePurchase Orders 21 min read Field GuideJob costing and profitability tracking field guide for electrical contractorsTrack the actual labor, material, equipment, subs, and overhead a job ate, set it against the estimate, and find out which jobs actually made money.Job CostingProfitabilityLabor Burden 21 min read Field GuideIsolated ground receptacles for sensitive equipmentAn orange receptacle with a quieter ground path: what an isolated ground really does, why it gets mis-installed more than almost any other device, and where it actually helps.Isolated GroundIG ReceptacleNEC 250.146 21 min read Field GuideIntrusion alarm system installation and design field guideDesign the detection layers and place the sensors to catch a real entry without the false alarms, then run dual-path signaling, verification, and a walk test.Intrusion AlarmFalse Alarm ReductionAlarm Verification 21 min read Field GuideHot work permit and fire safety field guide (NFPA 51B)Prohibit, relocate, or protect the work, clear 35 ft, keep a fire watch during and after, and sign the permit that forces the checks.Hot Work PermitNFPA 51BOSHA 1926.352 21 min read Field GuideGround ring electrode field guide (NEC 250.52(A)(4)) for electriciansWhat a ground ring is, the 20 ft of bare 2 AWG copper at 30 in deep, how to connect and bond it into the grounding electrode system, and why it gets done before backfill.Ground RingNEC 250.52Grounding Electrode 21 min read Field GuideGround-fault protection of equipment (GFPE) field guideWhat GFPE protects, why it is not GFCI, what NEC 230.95 requires on large wye services, and the one-point neutral bond that stops the nuisance trips.GFPENEC 230.95Ground-Fault Protection 21 min read Field GuideGeneral conditions and project indirect costs field guideWhat general conditions are, how they differ from company overhead, why they run with the schedule, and how to estimate, track, and recover the indirect costs that quietly eat the margin.General ConditionsIndirect CostsProject Overhead 21 min read Field GuideFleet vehicle and driver safety program field guide for contractorsThe drive is the biggest risk most crews run all day. Screen and train the driver, secure the load, watch the data, and pay off the crash before it happens.Fleet SafetyDriver SafetyMVR Monitoring 21 min read Field GuideField time tracking and labor hours for electrical contractorsCapture each worker's hours against the job and the cost code so payroll is right, the job cost is real, and the next bid is priced from what the work actually took.Time TrackingLabor HoursCertified Payroll 21 min read Field GuideField service work order management for electrical contractorsThe work order is the one record of a job from the call to the cash. Capture it in the field, authorize the scope, track the status, and invoice straight from it.Work Order ManagementField ServiceDispatch 21 min read Field GuideField leadership and the construction foreman roleWhat a foreman actually does at the point of work to turn a good estimate into a profitable job: plan it, make it ready, own the budget, and lead the crew.Field LeadershipForemanCrew Management 21 min read Field GuideDC fast charging (DCFC) station design and installation guideSize the service before the charger: the transformer, switchgear, demand charges, load management, and the utility timeline that actually controls a DCFC site.DC Fast ChargingDCFCNEC Article 625 21 min read Field GuideConstruction estimating contingency and risk pricing field guidePrice the unknown on purpose: what contingency is, how it differs from profit, allowance, and management reserve, how design completeness and the AACE class size it, and how escalation and drawdown fit.ContingencyRisk PricingAACE Estimate Classes 21 min read Field GuideEquipment grounding conductor sizing field guide (NEC 250.122)Size the EGC by the overcurrent device, not the wire. Upsize it when the phase conductors grow, and pull a full one in every parallel raceway.Equipment Grounding ConductorNEC 250.122EGC Sizing 21 min read Field GuideElevator modernization and maintenance: a building owner's field guideAn elevator is licensed, code-governed equipment. The owner's real job is not the wrenching. It is managing the contract, planning the mod before the car strands tenants, and keeping up the required tests.Elevator ModernizationASME A17.1Maintenance Contract 21 min read Field GuideElectrical working clearance field guide: NEC 110.26 working spaceHold the clear space in front of the gear: the depth by voltage and condition, the width and height, the dedicated space above, the egress, and the storage that fails the inspection.Working ClearanceNEC 110.26Dedicated Equipment Space 21 min read Field GuideElectrical shock first aid, CPR, and AED field guideGet the power off before you touch the victim, then call 911 and run CPR and the AED, while the real fix is preventing the contact.Electrical ShockFirst AidCPR and AED 21 min read Field GuideElectric sign and channel-letter installation field guideA storefront sign is an electrical device, a structure, and a zoning matter at once. Get the disconnect, the foundation, and the permit right.Electric SignsChannel LettersNEC 600 21 min read Field GuideIn-building wireless DAS and public-safety radio field guideTwo systems live in the same conduit. Cellular DAS needs the carrier's consent, and public-safety ERCES is a code-mandated life-safety system that has to work in a fire and pass the AHJ.Public Safety DASERCESBDA 21 min read Field GuideCrane, rigging, and signaling safety field guideWhat safe lifting is, the four killers, and how to keep the crane clear of the lines, within the chart, the rigging rated, and everyone out from under the load.Crane SafetyRiggingOSHA Subpart CC 21 min read Field GuideConveyor and material-handling system installation field guideGuard the nip points, level and align the frame, track the belt, wire the drive and controls, and prove the safeties before you hand it over.Conveyor SafetyNip Point GuardingASME B20.1 21 min read Field GuideContractor insurance, bonding, and risk field guide for electriciansCarry coverage that is both required and enough, collect and track every COI, and price insurance and bonding into the bid.Contractor InsuranceSurety BondsWorkers Comp EMR 21 min read Field GuideConstruction document control field guide: drawings, revisions, and the current setKeep one controlled source of truth, incorporate every revision and pull the superseded sheets, get the current docs to the field, and mark the as-built as you go.Document ControlVersion ControlAs-Built Drawings 21 min read Field GuideCommercial intercom, paging, and mass notification design field guideDesign intercom, paging, and mass notification audio for one thing above features: a message people can actually understand.Mass NotificationSpeech IntelligibilityPaging Systems 21 min read Field GuideCertified payroll and prevailing wage field guide for public-works contractorsRead the wage determination, classify each worker by the work performed, pay the full wage plus fringe, and file an accurate certified payroll every week, on time.Prevailing WageCertified PayrollDavis-Bacon 21 min read Field GuideCell tower construction and antenna installation field guideWhat cell site work is, why falls and the structural loading govern the job, and how to erect, mount, cable, ground, and commission a tower to carrier and code.Cell Tower ConstructionAntenna InstallationTIA-222 21 min read Field GuideBusiness KPIs and dashboard metrics field guide for electrical contractorsThe handful of numbers that show whether the business is healthy: booked revenue, gross margin, close rate, utilization, AR days, backlog, and cash, reviewed on a cadence.Business KPIsDashboard MetricsGross Margin 21 min read Field GuideBid/no-bid and go/no-go decision field guide for contractorsDecide which jobs to chase before you spend the hours estimating them: score fit, client, risk, capacity, and the real chance to win.Bid/No-BidGo/No-GoWin Rate 21 min read Field GuideBattery energy storage systems (BESS) field guide: NEC 706 and NFPA 855The battery that cuts the demand charge is also the biggest fire-code problem on the job. Get the chemistry, the interconnection, and the thermal-runaway rules right, because the fire code governs this install as much as the electrical code.BESSNEC 706NFPA 855 21 min read Field GuideAutomatic gate operator installation field guideInstall the operator and a compliant gate with the full entrapment-protection package for the usage class: the inherent reverse, external photo eyes and sensing edges, and a gate with no climbable or reach-through gaps.Automatic GatesUL 325ASTM F2200 21 min read Field GuideAerial lift and MEWP safety field guideWhat a MEWP is, the three killers, and how to keep the machine firm, the worker in, and the boom clear of the lines.Aerial LiftMEWPANSI A92 21 min read Field GuideAccounts payable and supplier management field guide for electrical contractorsControl what you buy, from whom, at what price and terms, and pay it right, so the margin you estimated does not leak at the counter through price creep, double pays, and missed discounts.Accounts PayablePurchase OrdersThree-Way Match 21 min read Field GuideCommercial access control system installation field guideDesign and install by the door: the credential, reader, controller, and electric lock, with free egress and fire-alarm release proven on every opening.Access ControlFail-Safe vs Fail-SecureOSDP Readers 21 min read Field GuideWireways and auxiliary gutters field guide for electrical crewsTell the wireway from the gutter, hold the 20 percent fill, keep splices under 75 percent, support it, bond it, leave the cover accessible, and size it for the bend.WirewayAuxiliary GutterNEC 376 21 min read Field GuideUfer ground (concrete-encased electrode) field guide for electriciansWhat qualifies as a concrete-encased electrode, when the NEC forces you to use it, the listed connection, and why it all has to be done before the concrete is placed.Ufer GroundConcrete-Encased ElectrodeNEC 250.52 21 min read Field GuideTransformer types: dry-type vs liquid-filled field guidePick the transformer type from location, kVA, voltage, fire, and efficiency: dry-type or liquid-filled, ventilated or cast resin, mineral oil or less-flammable ester.Dry-Type TransformerLiquid-Filled TransformerNEC Article 450 21 min read Field GuideTransformer acceptance testing and the turns ratio (TTR) field guideProve the transformer before you energize it: the turns ratio, the insulation, the winding resistance, the polarity, and the tap, then record the baseline the maintenance crew will trend against.Transformer TestingTurns Ratio TestNETA ATS 21 min read Field GuideThree-Phase Power: Wye vs Delta Field GuideHow three-phase power works in the field: wye and delta connections, line versus phase voltage and current, the square root of three, common services, and the high leg.Three-PhaseWye and DeltaLine and Phase Voltage 21 min read Field GuideShort circuit and available fault current study field guideWhat the study calculates, why under-rated gear fails on a fault, how the available fault current is found at each point, and how the ratings get verified before turnover.Short Circuit StudyAvailable Fault CurrentAIC SCCR 21 min read Field GuideReceptacle types and NEMA configurations field guideRead the device number off the face, match the configuration to the circuit and the load, and stop adapting around the keying that exists to keep the wrong plug out.NEMA ConfigurationsReceptacles14-50 Outlet 21 min read Field GuidePower factor correction and capacitor banks for electrical crewsRead the kW, kVAR, and kVA triangle, size the capacitor bank to a target power factor, and keep the caps off the harmonics that blow them.Power FactorCapacitor BankkVAR Correction 21 min read Field GuidePool and spa equipotential bonding field guide (NEC 680)Tie every conductive part in and around the water into one equipotential plane, bond the water, and get it inspected before the deck buries it.Pool BondingNEC 680Equipotential Bonding 21 min read Field GuidePhotovoltaic (PV) system wiring field guide: NEC Article 690Wire the array into a code-legal system: DC strings sized for the cold, rapid shutdown, the disconnects, grounding, and the interconnection that decides whether the breaker even fits.PV WiringNEC 690Rapid Shutdown 21 min read Field GuideOvercurrent protection field guide: breakers and fusesWhat a breaker or fuse actually protects, how each trips on an overload versus a short circuit, why the interrupting rating cannot be exceeded, and how the device gets sized and set.Overcurrent ProtectionCircuit BreakersFuses 21 min read Field GuideNEMA enclosure ratings and how to pick the right typeMatch the enclosure rating to the environment, then hold that rating through the door, the gasket, and every conduit entry you cut into the box.NEMA 250NEMA 4XEnclosure Ratings 21 min read Field GuideNEC box fill sizing and calculation for electrical crewsCount the conductors, the devices, the grounds, and the clamps, total the cubic inches, and prove the box is big enough before the cover goes on.Box FillNEC 314.16Outlet Box 21 min read Field GuideMotor starting methods: DOL, soft starter, and VFDWhy a motor draws six times its running current at start, what every reduced-voltage method trades away to cut that inrush, and how the load and the supply pick the method for you.Motor StartingSoft StarterWye-Delta Starting 21 min read Field GuideMotor bearing lubrication and VFD shaft grounding field guideKeep motor bearings alive: the right grease, the right amount and interval, and shaft grounding on VFD motors that would otherwise flute the races.Motor BearingsBearing LubricationVFD Shaft Grounding 21 min read Field GuideLow-voltage and Class 2 systems cabling field guideClassify the circuit, pick the cable by the space and its flame rating, keep it off the power, support it, hold the bend radius, then test what you built.Low VoltageClass 2 CircuitsStructured Cabling 21 min read Field GuideLockout tagout and electrically safe work condition field guideIsolate every source, lock and tag each one, release the stored energy, and prove the circuit dead before a hand goes near it.Lockout TagoutLOTOOSHA 1910.147 21 min read Field GuideLighting controls and dimming: 0-10V, DALI, and the driver matchPick the dimming protocol, match the LED driver to it, wire the control pair as Class 2, and commission the sensors and trim so the savings the code requires actually show up.Lighting Controls0-10V DimmingDALI 21 min read Field GuideKnob and tube wiring: assessment and remediationIdentify the old porcelain-and-cloth K&T, judge it by condition instead of age, find the buried and modified runs, and remediate with a qualified electrician.Knob and TubeNEC 394Old Home Wiring 21 min read Field GuideGrounding vs bonding explained for electriciansThe difference the whole trade confuses: bonding gives fault current a path back to the source to trip the breaker, grounding ties the system to earth, and the dirt clears nothing.Grounding vs BondingBondingEquipment Grounding Conductor 21 min read Field GuideGFCI and AFCI protection: where the NEC requires eachTwo devices, two jobs: the GFCI protects the person from a shock, the AFCI protects the building from an arcing-fault fire. Know which the code wants where.GFCIAFCINEC 210.8 21 min read Field GuideGenerator grounding and bonding: the separately derived system questionDecide whether the set is a separately derived system, put the one neutral-ground bond in the right place, give an SDS its own electrode, and verify one bond and only one.Generator GroundingSeparately Derived SystemNEC 250.30 21 min read Field GuideEmergency and standby power systems: NEC 700, 701, and 702 explainedClassify the load first, because the class decides the transfer time, the wiring separation, the coordination, and the testing. Get the class wrong and everything downstream is wrong with it.Emergency PowerNEC 700NFPA 110 21 min read Field GuideElectrical troubleshooting and multimeter testing field guideFind the fault by reasoning and measurement, not by swapping parts, and prove the meter and the circuit dead before you ever trust a zero.MultimeterTroubleshootingCAT Rating 21 min read Field GuideSurge protective device (SPD) types and NEC requirements field guidePick the right SPD Type for the location, mount it on short straight leads, size VPR and MCOV to the system, and replace it when the indicator goes dark.Surge ProtectionSPD TypesNEC 230.67 21 min read Field GuideElectrical submetering and energy monitoring field guideMeasure the tenants and loads below the utility meter with a meter and current transformers, get the CT phase and polarity right, and pick revenue-grade accuracy when the number turns into a bill.SubmeteringEnergy MonitoringCurrent Transformers 21 min read Field GuideElectrical splices, terminations, and connectorsPick the right listed connector for the conductor, prep it without nicking, torque it to the label, and put the splice where someone can get to it.SplicesTerminationsWire Connectors 21 min read Field GuideElectrical service and panel upgrade field guideRun the load calc first, raise the amperage only if it needs it, pull the recalled panel, update the grounding, and let the utility cut the power, not you.Service UpgradePanel ReplacementNEC Article 230 21 min read Field GuidePull and junction box sizing with NEC 314.28 for electrical crewsSize the pull box from the conduit geometry, not the conductor count, so the big conductors have room to pull and bend without damage before the cover goes on.Pull BoxNEC 314.28Junction Box 21 min read Field GuidePhase rotation and motor direction field guideWhat phase sequence is, why the wrong rotation spins a pump, fan, or compressor backward, how to reverse a motor by swapping two leads, and how to check direction before you energize.Phase RotationPhase SequenceMotor Direction 21 min read Field GuideParallel conductors and NEC 310.10(G) for electrical crewsRun two or more conductors per phase as one circuit, keep every conductor identical so they share the current, and put a full-size ground in each raceway.Parallel ConductorsNEC 310.10(G)Equipment Grounding 21 min read Field GuideHow to read an electrical one-line diagram: symbols and ANSI device numbersRead the one-line top down, source to load, decode the symbols and ANSI device numbers, and know why an out-of-date one-line gets people hurt.One-Line DiagramSingle-Line DiagramIEEE 315 Symbols 21 min read Field GuideMotor protection and overload relays for electrical crewsTwo faults, two devices: the overload relay holds the running current that cooks the windings, and a separate breaker or fuse clears the short circuit and ground fault.Motor ProtectionOverload RelayNEC Article 430 21 min read Field GuideHow to read a three-phase motor nameplateEvery rating you need to wire, protect, size, and replace a motor lives on the plate. Read it right and it sets the conductor, the overload, the starter, and the spare.Motor NameplateFLA vs FLCNEMA Code Letter 21 min read Field GuideInsulation resistance (megger) testing field guide for electrical crewsRead the insulation before it faults: match the DC test voltage, correct the reading to 20 degrees C, trend it against the baseline, and discharge the cable when you are done.Insulation ResistanceMegger TestingPolarization Index 21 min read Field GuideHazardous (classified) locations field guide for electriciansClassify the area first, then match every piece of equipment and the seal at every conduit to the class, division or zone, group, and temperature the study calls out.Hazardous LocationsNEC Article 500Explosionproof 21 min read Field GuideGrounding system testing and soil resistivity field guideMeasure the electrode's resistance to earth the accurate way, read soil resistivity for the design, know when the clamp-on lies, and record the number with its conditions.Ground Resistance TestingSoil ResistivityFall-of-Potential 21 min read Field GuideGenerator paralleling and synchronization field guideMatch the voltage, the frequency, the phase angle, and the rotation before the breaker closes, share the kW and the kVAR cleanly, and protect the bus against a set that motors.Generator ParallelingSynchronizationLoad Sharing 21 min read Field GuideGenerator load bank testing field guide for electrical crewsPut a real load on the set, prove it holds voltage and frequency at the nameplate, and for a diesel burn off the wet stacking that light running leaves behind.Load Bank TestingWet StackingNFPA 110 21 min read Field GuideFeeder and branch circuit design and sizing per NECWhere the service, feeder, and branch sit, how the 125 percent continuous rule sizes each, and how the conductor, the OCPD, and the ground stay matched.Feeder SizingBranch CircuitNEC 215 21 min read Field GuideElectrical estimating, takeoff, and bidding field guideCount the work, convert it to labor hours, price the material, add overhead and profit, and protect the number with a written scope.Electrical EstimatingTakeoffLabor Units 21 min read Field GuideElectrical disconnect switch types and code requirementsPick the disconnect by the load and the location, put it within sight where the code says, make it lockable, and write down what it controls.Disconnect SwitchSafety SwitchWithin-Sight Rule 21 min read Field GuideElectrical device wiring: receptacles and switches field guideLand the hot, neutral, and ground on the right screws, use the screws and not the back-stabs, torque to spec, and pigtail so the device is not carrying the downstream load.Device WiringReceptacles and SwitchesMulti-Wire Branch Circuit 21 min read Field GuideElectrical conductor color code and phase identification field guideTell the phases, the neutral, and the ground apart the way the code and the trade do, mark what the NEC actually fixes, and verify the rest with a meter.Conductor Color CodePhase IdentificationNeutral Conductor 21 min read Field GuideCable tray systems and installation field guide for electrical crewsPick the tray type, hold the fill and the load class, bond every splice, leave the expansion gaps, and dress the cable so it passes on looks and on the meter.Cable TrayNEC Article 392Cable Management 21 min read Field GuideUnderground cable fault locating field guide for electrical crewsFind where the cable failed before you dig: confirm the fault, prelocate the distance with TDR or a surge, then pinpoint the spot with the thumper and the ground microphone.Cable Fault LocatingTDRCable Thumper 21 min read Field GuideDistribution equipment field guide: switchgear, switchboard, panelboard, MCCMatch the gear to the level: switchgear, switchboard, panelboard, and MCC, with the fault rating, the drawout question, the clearance, and the record each one demands.SwitchgearSwitchboardPanelboard 21 min read Field GuideBuilding a UL 508A control panel and getting the SCCR rightWhat a listed industrial control panel is, why the short-circuit current rating is the number that decides whether it ships, and how the weakest power-circuit component sets it.UL 508ASCCRNEC 409 21 min read Field GuideConduit bodies and fittings: types and installation for electrical crewsPick the conduit body by where the cover faces, use it as a pull point, splice only where the volume is marked, and size it so the conductors have room to bend.Conduit BodiesConduit FittingsLB Fitting 21 min read Field GuideConduit bending fundamentals for electrical crewsBend EMT, IMC, and rigid clean and accurate: set the stub from the deduct, the offset from the multiplier, the saddle from its marks, and stay under the 360-degree limit.Conduit BendingEMT BenderOffset Multiplier 21 min read Field GuideConductor types and insulation: THHN, THWN, XHHWRead the letter code on the jacket, match the insulation to the location and the termination, then size from the column the wire and the lug both allow.Conductor InsulationTHHN THWNXHHW 21 min read Field GuideBuck-boost transformers: small voltage adjustment field guideHow a buck-boost transformer trims a slightly-off supply: insulating transformer field-connected as an autotransformer, kVA sizing off the manufacturer table, buck versus boost, single and three-phase, and the 208 to 230 motor case.Buck-Boost TransformerAutotransformerVoltage Correction 21 min read Field GuideArc flash PPE categories and arc-rated clothing field guideWhat the arc-rated clothing is for, how to pick it from the label or the table, and the layer rule that decides whether a burn is survivable.Arc Flash PPENFPA 70EArc Rated Clothing 21 min read Field GuideArc energy reduction methods field guide for electrical crewsHow to cut the incident energy at a piece of gear by clearing the fault faster, which methods NEC 240.87 and 240.67 accept, and how to keep coordination while you do it.Arc Energy ReductionNEC 240.87NEC 240.67 21 min read Field GuideAluminum branch wiring: hazards and remediationTell the old solid branch aluminum from a modern feeder, find the connection that overheats, and remediate it with a CPSC-recognized repair by a qualified electrician.Aluminum WiringCO/ALR DevicesCOPALUM Repair 21 min read Field GuideWiring methods, raceways, and conduit types for electrical crewsPick the raceway or cable by the location, the exposure, and the protection it needs, then support it, bend it, and ground it the way the method demands.Wiring MethodsConduit TypesRaceway 21 min read Field GuideInstalling and commissioning a variable frequency drive (VFD)Size the drive to the motor current and the load type, protect both ends with the right reactor and cable, ground the shaft, then prove it on no load before the load ever turns.Variable Frequency DriveVFD InstallReflected Wave 21 min read Field GuideConcrete-encased underground duct bank field guide for electrical crewsLay out the conduit grid, hold the spacing and cover, tie it down so it does not float, and get the pre-pour inspection right because the concrete is the last word.Duct BankConcrete EncasedUnderground Raceway 21 min read Field GuideTermination torque QA field guide for electrical crewsTorque every connection to the manufacturer's value with a calibrated tool, mark it, confirm it runs cool under load, and write the value down.Termination TorqueNEC 110.14Calibrated Torque Tool 21 min read Field GuideTemporary power field guide for construction sitesSet the temp service, hold the GFCI rule, keep the cords and lights safe, size the load, and document the daily checks before the permanent service energizes.Temporary PowerNEC 590OSHA 1926.404 21 min read Field GuideStandby generator and transfer switch installation field guideSize the set for the motor starting, set the pad and the clearances, get the fuel and exhaust right, ground the neutral correctly, and turn over a system that actually runs in an outage.Standby GeneratorTransfer SwitchNEC 700 21 min read Field GuideSelective coordination of overcurrent devices field guideWhy only the device nearest the fault should open, how fuses and breakers get there, what the NEC mandates for critical power, and where it collides with the arc-flash study.Selective CoordinationOvercurrent ProtectionNEC 700 21 min read Field GuidePanelboard installation and circuit directory field guideSet the panel where it belongs, terminate it to spec, bond the neutral in the one place it belongs, and leave a directory the next person can actually read.PanelboardLoad CenterNEC Article 408 21 min read Field GuideMotor control center (MCC) commissioning field guideReceive the lineup, megger and torque the bus, set every overload to the motor nameplate, and prove the control and the rotation before the load ever turns.Motor Control CenterMCC CommissioningOverload Protection 21 min read Field GuideMotor circuit conductor sizing per NEC Article 430Size the conductor, the overload, and the short-circuit device by three different rules off two different currents, then write down which number drove each part.Motor CircuitsNEC Article 430FLC vs FLA 21 min read Field GuideLightning protection system field guide (NFPA 780)Give the strike a path around the building, bond everything to one ground, and protect the electronics with surge devices, not the rods.Lightning ProtectionNFPA 780Air Terminals 21 min read Field GuideCommercial LED lighting retrofit and upgrade field guidePick the retrofit path, wire the tube safely, add the controls the energy code makes you add, dispose of the old lamps as universal waste, and chase the rebate.LED RetrofitBallast BypassType B LED Tube 21 min read Field GuideInfrared thermography inspection field guide for electrical equipmentRead the heat before the connection fails: load the gear, compare the phases, judge delta-T against NETA, and write the find down so it gets fixed at the right outage.Infrared ThermographyNETA CriteriaNFPA 70B 21 min read Field GuideHarmonics and power quality field guide for electrical crewsFind the nonlinear load that is heating your neutral and transformer, read THD and TDD against IEEE 519, and pick the mitigation that actually fixes it.HarmonicsPower QualityIEEE 519 21 min read Field GuideGrounding electrode system and bonding field guide for electrical serviceBond every electrode into one system, keep the neutral-ground bond at the service only, size the GEC right, and record what got connected.Grounding Electrode SystemBondingNEC 250 21 min read Field GuideFire alarm system installation and acceptance testing field guideInstall the panel and the devices, wire the circuits supervised, size the battery and the NAC, then pass the 100 percent acceptance test and hand over the record.Fire AlarmNFPA 72Notification Appliances 21 min read Field GuideFeeder tap rules under NEC 240.21 for electrical crewsA tap is a smaller conductor pulled off a feeder with no breaker at the connection. The tap rules let it run a short distance under fixed conditions on length, ampacity, and termination.Feeder TapsNEC 240.2110-Foot Tap Rule 21 min read Field GuideEV charger (EVSE) installation and commissioning guideMount the charger, run the branch circuit, set the load management, and commission it with a real charge instead of an energized box and a thumbs-up.EV ChargingEVSENEC Article 625 21 min read Field GuideEmergency and egress lighting: backup power, the 90-minute rule, and testingLight the path of egress, hold it for 90 minutes on the backup, pick the right source, and run the monthly and annual tests that keep the fire marshal off your back.Emergency LightingEgress LightingNFPA 101 21 min read Field GuideElectrical service entrance and metering installation field guideBring the utility power in, set the meter, land the disconnect nearest the entry, bond the neutral once at the service, and get the green tag before the utility energizes.Service EntranceMeteringNEC Article 230 21 min read Field GuideElectrical load calculation per NEC Article 220Total the connected load, apply the demand factors, and the calculation returns the minimum service or feeder size, not the impossible sum of every nameplate at once.Load CalculationNEC Article 220Demand Factors 21 min read Field GuideDry-type transformer sizing and installation field guideSize the transformer in kVA from the load, protect it per 450.3, ground the secondary as a separately derived system, and keep the heat moving.Dry-Type TransformerNEC Article 450Transformer Sizing 21 min read Field GuideConduit fill per NEC Chapter 9 for electrical crewsSize the raceway from the conductor schedule: sum the areas, pick the conduit type, hold the percent fill, and check that a legal fill is also a good pull.Conduit FillNEC Chapter 9Raceway Sizing 21 min read Field GuideConductor ampacity and NEC derating for electrical crewsStart at the 90C ampacity, correct for ambient heat, adjust for bundling, then cap the result at the lowest-rated termination before you trust the number.Conductor AmpacityDeratingNEC 310.16 21 min read Field GuideCommercial lighting design: footcandles, layout, and controlsSet the footcandle target for the task, lay the fixtures out for uniformity, hold the power density the energy code allows, and commission the controls the code makes you install.Lighting DesignFootcandlesLighting Controls 21 min read Inspection PacketCable reel receiving and remainder log for the wire yardVerify the put-up against the footage markers, log the heat number, and keep a running balance on every reel so the field finds the wire instead of re-buying it.Cable ReelWire YardMaterial Control 20 min read Field GuideCable pull planning and the tension card for feeders and MVPlan the pull, calculate the max tension and sidewall pressure, and hand the crew a tension card so the feeder goes in without damage you cannot see.Cable PullingPulling TensionSidewall Bearing Pressure 21 min read Field GuideBusway and bus duct installation field guide for electrical crewsReceive it dry, torque every joint to the manufacturer value, support it on the rated spacing, megger it before energizing, and scan it hot once it is loaded.BuswayBus DuctNEC 368 21 min read Field GuideAutomatic transfer switch commissioning field guidePull the normal source, time the transfer, force the retransfer, prove the bypass, and record the time delays the owner inherits.Automatic Transfer SwitchATS CommissioningNEC 700 21 min read Field GuideAEGCP field guide for temporary power on construction sitesRun a written assured equipment grounding conductor program when GFCI nuisance trips on long temp feeders and big tools make the GFCI path unworkable.AEGCPTemporary PowerOSHA 1926.404 20 min read Field GuideArc flash study and labels field guide for electrical crewsWhat the arc-flash study calculates, what the label has to carry, and how the safety program keeps a worker off the wrong side of the boundary.Arc FlashNFPA 70EIEEE 1584 21 min read Direct AnswerPoE voltage drop and bundle heat field guideWhy high-power PoE is limited by delivered watts and bundle heat, how the 802.3bt classes really pencil out, and what to do when a long run underpowers the device.PoE802.3btBundle Heat 20 min read Direct AnswerEV feeder sizing walkthrough: conductors, OCPD, and the 125 percent ruleSize the conductor and breaker for an EV charger as a continuous load, check the drop over the run, and know when load management beats upsizing the service.EV ChargingNEC Article 625Feeder Sizing 20 min read Direct AnswerVoltage drop field guide for electrical crewsCalculate voltage drop, size the conductor, hold the right limit, and record the assumption that drove the decision.Voltage DropNEC 215Feeder Sizing 20 min read
Browse every electrical question, answered

Electrical calculators

Bolt torque calculatorEstimate bolt torque from the target preload: T = K x D x F, where K is the nut factor.Sling load calculatorFind the tension in each sling leg: (load weight / legs) divided by the sine of the sling angle from horizontal.Energy cost calculatorFind what a load costs to run: kWh = kW x hours, times the rate per kWh, per day and per year.Footcandle calculatorEstimate fixtures for a target light level: target lumens = area x footcandles, divided by the lumens each fixture delivers.Generator runtime calculatorFind how long a generator runs: usable fuel in gallons divided by the consumption in gallons per hour.Generator sizing calculatorSize a generator from the running load plus the largest motor's starting surge, with headroom: peak = running + surge.kVA to amps calculatorConvert kVA to full-load amps (or amps back to kVA) for single-phase and three-phase, from the voltage.Markup & margin calculatorConvert between markup and margin and price a job right: enter your cost and a target margin, target markup, or price, and get the price, profit, markup %, and margin %.Ohm's law calculatorEnter any two of voltage, current, resistance, and power, and the calculator solves the rest with Ohm's law.Watts to amps calculatorFind single-phase current from power: amps = watts divided by (volts x power factor).Solar production calculatorEstimate solar energy: kWh = system kW x peak sun hours x a derate factor, per day and per year.Three-phase power calculatorFind three-phase kW and kVA from volts, amps, and power factor: kVA = sqrt(3) x V x A / 1000, and kW = kVA x PF.Voltage drop calculatorSize the conductor against the run: enter the load and length, get the volts dropped and the percent against the 3 percent target.

Electrical readiness checks

Arc flash readinessA 2 minute check on whether your electrical safety program would actually protect a worker from an arc flash, before an incident or an OSHA inspector tests it.Cash flow readinessA 2 minute check on whether you run a WIP, bill early, and collect fast, before a profitable company runs out of cash.Contractor business healthA 2 minute check on whether your trade business is run on numbers and cash discipline, before a profitable-looking year quietly turns into a payroll you cannot make.Conveyor safety readinessA 2 minute check on whether your conveyor is guarded, e-stopped, locked out, and aligned, before a nip point takes a hand or a jam-clear takes a worker.Cathodic protection checkA 2 minute check on whether your CP system is coated, sized, proven to criterion, and monitored, before corrosion eats a pipeline, tank, or structure you thought was protected.Crane & rigging readinessA 2 minute check on whether your crane pick is planned, rigged, and signaled to land safely, before a dropped load or a tip-over proves it was not.Sign install readinessA 2 minute check on whether your electric sign has the code disconnect, the wind-rated structure, and the permit, before it fails inspection or comes down in a storm.Electrical safety and LOTOA 2 minute check on the electrical safety practices that decide whether a worker goes home, before an arc flash or a re-energized circuit decides for you.Elevator readinessA 2 minute check for owners and PMs on whether your elevators are under the right contract, modernized in time, and kept up to code, before they strand tenants.Energy audit readinessA 2 minute check on whether your energy effort starts with the data, captures the free operational savings, and proves the results.Estimating health checkA 2 minute check on whether your bids actually recover your costs and win the right work, or quietly bleed margin one job at a time.Fleet & DOT readinessA 2 minute check on whether your service trucks and drivers would pass a DOT review and keep your crews safe, before a roadside inspection or a crash finds the gaps.Surety bonding readinessA 2 minute check on whether you understand surety bonds and have the financials, WIP, and relationship to grow your bonding capacity.Safety wearable readinessA 2 minute check on whether your safety wearables are calibrated, wired to a real response, and actually worn, before you trust them to catch a gas, fall, or heat event.Hot work safety checkA 2 minute check on whether your welding, cutting, and compressed-gas work has the permit, fire watch, clearance, and cylinder controls to avoid a fire or an explosion.

Compare Electrical options

Cable tray vs conduitCable tray vs Conduit racewayCopper vs AluminumCopper conductors vs Aluminum conductorsDry-type vs liquid-filledDry-type transformer vs Liquid-filled transformerEMT vs RMCEMT vs Rigid metal conduit (RMC)Fuses vs breakersFuses vs Circuit breakersGFCI vs AFCIGFCI protection vs AFCI protection

Electrical field tools

PoEHeatPoE voltage drop, bundle heat, conduit fill, and 802.3bt checks.EVFeederEV charger load, voltage drop, and feeder planning.Pull Plan CardCable pull planning and turnover card export.Storm Crew Day LogOffline storm crew timesheet, per-diem, lodging, equipment, mileage, and export records for mutual-aid foremen.Reel Remainder LogOffline cable reel balance log, pull history, partial-reel estimator, low-reel dashboard, and yard export packets.Assured Ground RouteOffline AEGCP color-route log for cord sets, temporary receptacles, tools, continuity readings, failed-item holds, and export records.Alarm Sweep 72Scans fire alarm devices, logs smoke detector sensitivity due dates, and exports NFPA 72 test records.AmpRightOffline electrical field tool for crews.BendRight DCOffline conduit bend calculator with cut list and phone angle check for electricians.CertPrep DCNICET fire alarm practice test app with NETA, NCCER, and NFPA 70E drills.Clearance ProofBefore and after span proof for utility line-clearance crews with GPS, clearance math, and sealed packets.Conduit Bid-in-a-TruckCounts devices and conduit footage into a line-item electrical bid from the truck, offline.Deficiency Tag LoopWrites consistent fire-life-safety deficiency wording with stamped photos and re-inspect tracking, offline.DGA Bottle Chain of CustodyTracks transformer oil DGA sample bottles with labels, photos, GPS, and custody export packages.DoorCertRuns AAADM-style automatic door inspections against ANSI limits and exports a signed PDF per door.Transformer Oil DGA ReaderGrades transformer oil, plots Duval triangle and pentagon, and exports per-unit field reports offline.FireBatt 72Builds an NFPA 72 fire alarm battery calc and point-by-point NAC voltage-drop worksheet for the AHJ.Foot Candle GridVerifies exterior lighting foot-candle readings against the approved photometric plan with uniformity and PASS/FAIL.GangBox DC ApprenticeOffline how-to cards, take-up marks, jargon decoder, and checkoffs for first-year electrical apprentices.Illegal Attach TallyPhoto-backed pole attachment audits for joint-use field walks, tallying exposure and exporting a review record.OhmGround FOPPlots fall-of-potential ground resistance readings, checks the 62% value, and exports a field report.Oil Pass GateRecords transformer oil and electrical acceptance tests offline with witness sign-off and evidence export.Pad-Mount Receiving CheckDocuments pad-mount transformer receiving with photos, nameplate compare, and locked signed records.Pay App SOVOffline G702/G703 SOV billing, retention, T&M, and closeout tracking for subcontractors.PitWitness Test-WellLogs ground test-well readings along routes with trends, GPS stamps, and photo evidence.Reel ReceivingInspects cable reels at the dock, photographs damage, tracks the claim clock, and builds receiving packets.Sag Field CardGives line crews a PASS or FAIL conductor sag card checked against the issued stringing chart.StaticFloor S20.20Logs ESD floor resistance and walking-body-voltage against the S20.20 pass-fail grid.Storm Force-Account LogLogs storm labor, equipment, photos, and force-account packets for utility and public works crews.Storm Material SlipBuilds GPS-tagged material slips for storm line crews and sends a clean PDF yard request from the pole.SunVaultOffline off-grid solar sizing for panels, battery bank, inverter, and charge controller from real loads.Sweep Radius CheckLogs conduit bends and sweep radius for duct-bank crews before backfill.