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ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR
AFCIs ARC FAULT CIRCUIT INTERRUPTERS
ALUMINUM WIRING HAZARDS & REPAIRS
AMPS VOLTS DETERMINATION
AMPERAGE MEASUREMENT METHODS
ANALOG VOMs & MULTIMETERS
APPLIANCE EFFICIENCY RATINGS
BACKUP ELECTRICAL GENERATORS
BACK-WIRED ELECTRICAL DEVICES
BOOKSTORE - ELECTRICAL
CADET & ENCORE HEATER RECALL
CHALLENGER ELECTRIC PANELS
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
Classified CIRCUIT BREAKER WARNING
CUTLER HAMMER PANEL FIRE
CORROSION in ELECTRICAL PANELS
DEFINITIONS of ELECTRICAL TERMS
DIRECTORY OF ELECTRICIANS
DMM Digital Multimeter HOW TO USE
ELECTRIC METERS & METER BASES
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRIC PANEL AMPACITY
ELECTRIC PANEL INSPECTION
ELECTRIC PANEL MOISTURE
Electric Power Frequency Table
EMF RF FIELD & FREQUENCY DEFINITIONS
ELECTRICAL GROUND SYSTEM INSPECTION
ELECTRICAL SERVICE DROP
ELECTRICAL SERVICE ENTRY WIRING
ELECTRICAL SPLICES, HOW TO MAKE
ELECTRICAL WIRING COLOR CODES
EMF RF FIELD & FREQUENCY DEFINITIONS
FIRE SAFETY Checklist, CPSC
GFCI PROTECTION,Testing GFCIs AFCIs
HEATING COST FUEL & BTU COST TABLES
HEAT TAPE USAGE GUIDE
Hertz - Definitions of KHz MHz GHz THz
KNOB & TUBE WIRING
LIGHTING, EXTERIOR GUIDE
LIGHTING, INTERIOR GUIDE
LIGHTNING PROTECTION SYSTEMS
LOW VOLTAGE BUILDING WIRING
LOW VOLTAGE TRANSFORMER TEST
MAIN ELECTRICAL DISCONNECT
MAIN DISCONNECT AMPACITY
MOISTURE SOURCES in PANELS
MURRAY SIEMENS Recall
PHOTOVOLTAIC POWER SYSTEMS
PUSHMATIC - BULLDOG PANELS
REMOTE ELECTRIC POWER, PHOTOVOLTAIC
RUST in ELECTRICAL PANELS
SAFETY for ELECTRICAL INSPECTORS
SE CABLE SIZES vs AMPS
SIEMENS MURRAY Recall
THERMAL EXPANSION of HOT WATER
THERMAL EXPANSION of MATERIALS
UNDERGROUND SERVICE LATERALS
VOLTS / AMPS MEASUREMENT EQUIP
VOLTAGE MEASUREMENT METHODS
WIND TURBINES & LIGHTNING
ZINSCO SYLVANIA ELECTRICAL PANELS
Main electrical panel inspection procedures & defects:
This article summarizes inspection of the building electrical panel, main panel, or electrical distribution and sub panels. This article series discusses procedures for safe and effective visual inspection of residential electrical systems including electrical panels and other components, when the inspection is conducted by trained building inspection professionals, home inspectors, electrical inspectors, and electricians.
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PANEL COVER - Residential Electrical Panel Cover Inspection and Special Safety Hazards - Look before you touch!
Information in this electrical inspection article series was presented by Daniel Friedman - InspectApedia.com, and discussed by the Hudson Valley chapter of the American Society of Home Inspectors - HVASHI Seminar 12 Sept 2002, Updated 2006, 2009, Jan 2014.
Before Touching or Opening the Electrical Panel for Inspection
CIRCUIT WIRING AMPS FUSING - Electrical branch circuit wiring amps/fusing defects - Copper electrical wiring
Match wiring gauge to ampacity - the following describe copper wire sized or gauges and the matching circuit ampacity or overcurrent protection that is required to be provided by fuse or circuit breaker:
Exceptions to these wire sizes and fusing occur for special circumstances such as air conditioners whose motors produce a brief current surge during startup.
MAIN DISCONNECT INSPECTION - Electrical Panel Main Disconnect Inspection - Do you Pull the Main Fuse or Test the Main Breaker?
Continue reading at ELECTRIC PANEL INSPECTION or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
(Nov 15, 2012) Leo Duprey said:
Steve Pettifer said:
Sounds strange to me too.
If this is a 2-pole breaker it could have an internal fault.
If the voltage change is small the fault may be in how it's being measured.
(June 1, 2014) Anonymous said:
Sounds as if we're either confusing volts and amps or you've connected or made a 120V circuit to a 240V circuit by crossing wires.
Not sure how you are measuring voltage nor if the procedure is safe, but in general you would expect to see similar voltage levels on each leg of a residential panel, around 120V.
You may be confusing amps and volts; current draw from plugging something in on a circuit shouldn't change the voltage level.
Voltage measurement is discussed at
If you have abnormal voltage entering the panel you should call your electric company for diagnosis and repair assistance and
WATCH OUT: if the cause for voltage drop is in your equipment, wiring, or on your property there may be close-by serious safety hazards.
Safety Warning: Opening an electrical panel and approaching any live electrical wiring, devices, & equipment is a dangerous procedure that can damage electrical equipment or worse, cause electrical shock, or even death.
Such procedures should not be undertaken unless the person conducting the examination is trained and competent to avoid electric shock. If the inspector is not trained for this procedure s/he should never insert any instrument or tool into electrical equipment.
(June 1, 2014) Steve Pettifer said:
Steve that's the sort of fault that left me worried about a site hazard - if wire is damaged and current is shorting somewhere; I've seen live electrical siding, porch railings, plumbing pipes, gas pipes.
Question: define open ground
(Sept 21, 2014) raul sanchez said:
It means not connected to earth
In turn, that means "unsafe" since the grounding system cannot protect the occupants or wiring system if the grounding path is incomplete;
Question: a 8 space 16 circuit panel and a 16 space 16 circuit panel?
(Jan 23, 2015) curious said:
In any case, 16 spaces means you can plug in 16 circuit breakers with each breaker occupying one slot in the panel.
An 8-space panel that claims to offer 16 circuits must be using a form of circuit breaker that allows two breakers to fit into a single slot in the panel
Question: source of lists of electrical panel problems
(Jan 24, 2015) Mike said:
40 years of building inspection, publications, research, teaching and attending professional conferences, talking with electricians and builders and home inspectors, reading research on electrical failures, IEEE, Holm Conference, ASME, and various trade associations. The original list of electrical distribution panel defects with which we started was scribbled out by a team of senior home inspectors, ASHI members, at a series of meetings intended to define an education curriculum as well as a basis for testing and certification exams for home inspectors. Ultimately ASHI decided not to follow the curriculum plans though of course, home inspection education companies lept into the gap.
But if you're saying you could add to the list, please do. None of us has a corner on the market of information.
Question: finding current with main breaker off
14 Feb 2015 LarryP said:
Watch out: this sounds very dangerous; I suspect a damaged service entry cable (with an internal short) or a damaged electrical panel or main breaker (some brands like FPE can remain "on" internally when switched off physically)
When I found the condition you described my brother-in-law, a theater electrician who didn't need to follow the NEC, had over-tightened BX connectors so that at many electrical boxes the neutral and hot were dead shorted. We found those quickly. But weaker shorts continued to trip GFCIs until we visited every single wire connection to find and re-make the faulty ones. Somewhere you may have a short hot to neutral or a failing electrical component giving the same effect.
Questions & answers or comments about procedures for and defects found in inspection of the electrical distribution panel.
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