Electrical panel & electrical systems: hazards, inspections, repairs, home page & article index.

This electrical wiring article 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.

We include questions and and answers about common defects in electrical panels that may be discovered by visual inspection, that is, without performing electrical tests.

Electric Panel Inspection Course Summary

Fatal Shock Hazard Warning: Inspecting electrical components and systems risks death by electrocution as well as serious burns or other injuries to the inspector or to others. Do not attempt these tasks unless you are properly trained and equipped.

The procedures discussed in this class require that the cover of the panel be removed in order to expose the panel interior.

Homeowners should not attempt this step, and no one lacking proper electrical safety training should remove the electrical panel cover nor attempt to perform the tasks discussed in this class.

ELECTRICAL CODE COMPLIANCE WARNING: these inspection procedures are designed to assist in the detection and reporting of electrical service defects which can be recognized by visual inspection.

This inspection is not for the purpose of determining compliance with local or national electrical codes. Guidelines given here, such as overhead wire clearances, are based on widely-accepted codes and standards, but local building codes may specify other or different restrictions.

[Click to enlarge any image]

This material was first presented by Daniel Friedman - InspectApedia.com, at the Hudson Valley chapter of the American Society of Home Inspectors - HVASHI Seminar 12 Sept 2002, Updated April 2006, April 2009, August 2011.

Part I - Electrical Panel Defect Identification - Principles

• Safety Procedures for Electrical Inspectors
• Electrical Power Delivery System
• Common Electrical Panel and Wiring Defects

Part II - Electrical Panel Defect Recognition - Photos of Electrical Defects & Examples

This section of the class contains annotated field photographs of certain electrical panel defects which can be recognized by visual inspection.

That is, no instruments, no measurements, and no insertion of any device into the electrical panel are required to perform these tasks. I have these photos on file and will add them to this presentation if readers request

Overview of the Residential Electrical System and Electrical Inspection Hazards

• The Electrical System Function is to power home systems/appliances, providing safe distribution of electrical power throughout the building.
• Costs: operation, repair, updating/expansion

Safety Procedures for Residential Building Electrical Inspectors

SAFETY WARNING: Inspection of electrical systems risks death by fatal electrical shock. The procedures discussed in this class require that the cover of the panel be removed in order to expose the panel interior.

Homeowners should not attempt this step, and no one lacking proper electrical safety training should remove the electrical panel cover nor attempt to perform the tasks discussed in this class.

Photo: at an electrical system inspeciton our client demostrated by a gentle tug on the grounding electrode that the installer had drive a cut-off too-short rod just a few inches into the soil, giving an unreliable local electrical ground. This was an improper, illegal, and unsafe electrical ground installation.

Electrical Panel Inspection Safety - Critical Warnings

Watch out: Do not:

• touch electrical equipment if you can see evidence of existing dangerous conditions (such as the missing electrical grounding electrode shown at left)
• touch SEC or other wires
• insert probes/tools into panel
• remove suspect panel covers. Later we explain that visual clues of water, leaks, short circuits, spring-loaded panel faces, all present possible electrocution hazards that can occur merely from touching or attempting to remove the panel cover).
• touch electrical equipment from unsafe location (wet, off balance, grounded - current flows from a hot wire through you, etc.)
• continue to touch or inspect the panel if you feel a charge, tingle, shock
• stand in water or in wet conditions while touching electrical equipment
• More electrical panel or distribution panel hazards to the inspector and to the property owner are
  
  at ELECTRICAL DISTRIBUTION PANELS

Watch out: : Protect nearby observers, clients, etc. from hazards [added by DF 2/13/2006]

• Do not permit observers to touch the inspector while that person is working on or at the electrical panel.
• Do not permit observers to touch the electrical panel nor to insert any tool, pencil, or other object into the panel.
• The inspector should stand with his/her body between observers and the panel, and should be prepared to physically block an attempt by the observer to reach towards or touch the electrical panel while its cover has been removed.
• Explain, calmly and without exaggeration, but accurately, the shock and fire hazards to observers and instruct the observers on what to do if the inspector him/herself is being shocked by the panel.
• [Don't touch a person being shocked. If a wooden board or stake is nearby, one might attempt to push the inspector away from the panel using that device or to turn off the main breaker or fuse. Call for help immediately.

Photo just above: at our request for some safe drama, our electrical inspection client illustrates our warning: a homeowner or other un-trained person should not remove the cover not ever touch anything inside the electrical panel.

Notice that in this photo it would be very easy to be touching both a grounded iron pipe (under her left hand) while touching a live electrical wire or connector.

That gives a direct path for current to flow through the human body, perhaps across the heart, for quick death.

Watch Out:  Do not attempt to work on your electrical wiring, switches, or outlets unless you are properly trained and equipped to do so. Electrical components in a building can easily cause an electrical shock, burn, or even death.

Even when a hot line switch is off, one terminal on the switch is still connected to the power source. Before doing any work on the switch, the power source must be turned off by set­ting a circuit breaker to OFF or removing a fuse.

See SAFETY for ELECTRICAL INSPECTORS and ELECTRICAL WIRING BOOKS & GUIDES

More Reading on Electrical Inspection Safety

Electrical inspectors planning to examine residential electrical panels, in addition to obtaining proper training, should read the following:

• SAFETY for ELECTRICAL INSPECTORS for Inspectors examining Residential Electrical Systems.
• AMPS VOLTS DETERMINATION - topic home, Dan Friedman and Alan Carson, updated through 2018 from an earlier article found in the ASHI Tech Journal Article, Vol.2. No.1, Winter 1992 p. 14-19. (Online, and original reprints available from the American Society of Home Inspectors). Sidebars provided with this article include a table of Electric Wire Sizes provided for the article by ASHI professionals Jules Falcone and Matthew Pinto.

Carson Dunlop Associates' sketch at page top shows where the electrical inspection starts at a residential property.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: can an electrical panel be mounted upside down?

Can a circuit breaker panel be installed upside down and still pass national and local electrical code inspections? - Mike On 2011-08-15

Reply: Circuit breakers that operate vertically should be mounted so that "up" is "on" and "down" is "off"

How to Mount an Electrical Panel: Panel Position and "upside down" electrical panel code provisions:

Mike:

Botttom line: YES in side-to-side breakers, NO in vertically-switched breakers

The short answer is that if circuit breakers are operating side to side it's not an issue but if breakers, in particular the main breaker, operates vertically, "UP" needs to be "ON" and "down" needs to be "off". We include NEC citations below.

Details:

According to a number of electricians forums we reviewed, contemporary electrical panel circuit breakers will function correctly in any position, and there are quite a few electricians who mount panels "upside down" with the mains at panel bottom, in particular if the SEC cables are entering from the bottom of the unit.

Just be sure that all panel labels including MAINS are properly oriented and legible so that the homeowners are not confused about which breaker controls which circuit.

There may however be both code (NEC) and user issues about breaker positions: in particular about clear "off" and on positions of circuit breakers in some electrical panel designs.

If the electrical panel MAINS switch operates "side to side" then you can mount the panel with either end "up" but if the MAINS switch operates "up and down" then putting the panel "upside down" would mean that "off" would be "up" - which is unsafe because that's not how most users think about switch on and off positions.

Perhaps part of the "off is down" convention derives from older knife-switch mains that were installed with "off = down" because of a concern that in the opposite position a worn or loose knife switch might fall from "off" (up) into on (down) in a panel - an unsafe condition.

See NEC 404.7. Also see NEC 240.81. That provision requires vertically-operating circuit breaker switches to be mounted so that "Up" is "On and "Down" is in the "Off" position.

 

Question: How do we know if an electric panel fuse has blown?

How do you know if say a solid type 40 amp four inch fuse on the condenser outside fan is blown? - Bruce

Reply: swap in a new fuse; remove the fuse and test it for continuity.

Bruce you're right that it may be impossible to tell that a cartridge type fuse is "blown" by simple visual inspection, unless by chance the fuse is discolored or deformed.

By contrast, round Edison-based fuses include a glass window through which you can observe the melted fusible link if that type of fuse has "blown".

In some countries cartridge type fuses actually use a re-usable cylinder into which a fusible link is inserted, can be removed, and can be inspected.

But a blown cartridge fuse will not conduct electricity from one end to the other - one could test such a fuse OUT OF THE PANEL (not in place in the panel, for safety reasons) using a multimeter or VOM in the Ohms setting.

Most homeowners simply swamp in a new fuse and see if that restores power.

Question: Is it safer to turn off all of the circuit breakers when inspecting an electrical panel?

If i want to visually inspect the wires behind the panel cover, could i just turn off all breakers to reduce the chances of shock if the panel hits a hot wire? Thanks!- JMW

Reply: Yes, ... and not exactly - electrical panel inspection tips

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem or spot an unsafe condition at the electrical panel, even before it is touched

See TOUCHING ELECTRICAL EQUIPMENT

Beginning at ELECTRICAL PANEL INSPECTION SAFETY I've already called out evidence of

water entry or rust (ELECTRIC PANEL MOISTURE), loose panel components, amateur workmanship,

hazards just in removing the electrical panel cover (ELECTRICAL PANEL COVER REMOVAL) and even arc burns or the

heads of sheet metal screws affixing the panel cover (ELECTRICAL PANEL COVER SCREWS) as red flags that mean that

even touching the panel (Touching Electrical Equipment), much less opening it or removing its cover, must be approached with extra care.

That said, here are some things to consider: Once an external inspection of the electrical panel, surrounding wiring and devices, and the panel cover and even other site clues of amateur workmanship or poor maintenance have been considered,

if you turn off the main circuit breaker to the panel it should de-energize all of the circuits below, making it unnecessary (and probably a mistake) to turn off individual circuit breakers.

Watch out: because there are serious safety hazards and risk of injury or death to the inspector or bystanders during an electrical inspection, be sure to review

SAFETY for ELECTRICAL INSPECTORS

Watch out: turning off the main circuit breaker in an electrical panel will not de-energize the main service entry lugs nor possibly other electrical panel components so potentially fatal electrical shock hazards remain.

Watch out: do not turn off circuit breakers at an electrical panel that is in use supporting an active, occupied building. There are risks of disabling or even damaging computer equipment and also certain medical equipment that might be kept running to support the health, safety, even life of building occupants in some situations.

Watch out: in certain electrical panels such as FPE Stab-Lok equipment, operating the circuit breakers by switching them on and off can actually increase the risk that later the breaker may fail to trip in response to an overcurrent, risking a building fire.

 

Use a spray to clean circuit breakers after they got wet?

Several months ago, I had some water drip down my lines and through my electrical panel. We dried it out & it seems ok now. However I recenly opened the panel and noticed a little rust around the breakers. Is there a spray that I can use to clean the breakers? - On 2012-12-29 by William Wotton -

Reply by (mod) - No, a cleaning spray would be inadequate and unsafe

Unfortunately once a circuit breaker has been wet there is serious risk of internal corrosion that can cause it to fail to operate properly. Corrosion of metal parts inside the breaker may jam its operation entirely or may slow its tripping, so that the breaker no longer gives the over-current, fire, and shock protection that was intended.

Wet circuit breakers should be replaced.

See RUST in ELECTRICAL PANELS

Do the brands of the service panel and the breakers inside need to be the same?

Does the brand of the service panel and the breakers inside need to be the same? - On 2020-09-08 by Janet Dempsey

Reply by (mod) - Manufacturers say yes.

Janet

Thank you for the helpful and important question.

According to the manufacturers of a number of electrical panel brands only OEM original equipment manufacturer brand circuit breakers should be used in their panels. I did in fact there have been some replacement or alternate brand circuit breaker failures.

Of course if you listen to the manufacturers of replacement circuit breakers they will tell you the breakers are fine.

So essentially she was a safety one. At least some replacement circuit breakers are unsafe and failed at a very high rate. There are examples in this article series under FPE replacement breakers for example, at FPE REPLACEMENT BREAKERS where we discuss UBI breakers - https://inspectapedia.com/fpe/Replacement_FPE_Circuit_Breakers.php

See important replacement circuit breaker failure rate details at UBI FPE CIRCUIT BREAKER TEST RESULTS - current test results showed a greater than 50% failure-to-trip rate

Are Splices Allowed inside the Electrical Panel?

Is it legal, according to NEC, to splice a current carrying conductor with a 'wire nut' within a circuit breaker panel? On 2020-06-18 by GIH -

Reply by Janet Dempsey - yes

GIH

Short answer: Yes, with some reservations on total space used. Please find your question and my detailed answer citing the US NEC now near the bottom of the article above on this page.

Thank you for asking.

Details: US NEC 312.8 Enclosures with Splices, Taps, and Through Conductors

Are splices allowed in the electrical panel? Text of US NEC 312.8 Enclosures with Splices, Taps, and Through Conductors

GIH

Thank you for a helpful question: are splices allowed in the electrical panel.

The answer is a "yes provided" ...

Electrical wire splices, including by using a twist-on connector or "wire nut" (that's a trade name), are permitted PROVIDED that the total collection of conductors and splicing materials do not fill the space to more than 75% of its cubic volume measured at any point as we will explain below.

Here's the electrical code citation from the US NEC 312.8

312.8 Enclosures with Splices, Taps, and Through Conductors

Cabinets, cutout boxes, and meter socket enclosures can be used for conductors feeding through, spliced, or tapping off to other enclosures, switches, or overcurrent devices where all of the following conditions are met:

(1) The total area of the conductors at any cross section doesn't exceed 40 percent of the cross-sectional area of the space.

(2) The total area of conductors, splices, and taps installed at any cross section doesn't exceed 75 percent of the cross-sectional area of that space.

Recommended: Mike Holt's Illustrated Guide to Changes to the NEC 2014, Mike Holt Enterprises, Mike Holt, Ryan Jackson.

Note: the 2017 NEC adds the following under 312.8

(3) A warning label complying with 110.21(B) is applied to the enclosure that identifies the closest disconnecting means for any feed-through conductors.

This is intended to handle the case in which the electrical panel or other enclosure has wires feeding *through* the panel from an external source to an external destination, and requires the electrician to include a warning that in essence tells a future worker that there are live wires running through the enclosure and whose power is controlled at an external source or switch located elsewhere.

How much free area is needed in front and at the sides of an electrical panel?

What is the area in front of a electric panel -free area to pass code -to access the pane -in front and the sides also On 2019-06-27 by Ross Cirrincione

What's the minimum distance required between in-wall plumbing, and an electrical service panel in Florida?

In Florida code, is there a minimum distance required between in-wall plumbing, and an electrical service panel? Thank you. - On 2015-05-18 by Martin -

Reply by Janet Dempsey - how much space must be left in front of an electrical panel

Ross: Typically you are going to require three feet of working distance

Martin: I have not found such a reference specifically constrained to plumbing but there are indeed panel working space requirements.

See details at ELECTRIC PANEL WORKING SPACE

Can I use a insulated copper ground wire

can I use a insulated copper ground wire of the proper size for a panel ground to earth On 2019-05-12 by gerold

Reply by Janet Dempsey (mod) -

Yes

 

Are KY state electrical inspectors required to attach an inspection sticker to a main panel which has been replaced and inspected.

Are KY state electrical inspectors required to attach an inspection sticker to a main panel which has been replaced and inspected. On 2018-12-11 by Chris

Reply by Janet Dempsey - Attach an inspection sticker to a main panel which has been replaced and inspected

I'm not sure I can say for every town in KY, since the inspector is the final legal Authority but that is a common custom in most code jurisditions. In Kentucky the use of electrical inspection stickers varies by city or jurisdiction within the state.

In Kentucky at http://dhbc.ky.gov/ed/ei/Documents/Elec%20Inspection%20Supplies%20Request.pdf you'll see that among the electrical inspection supplies that can be requested by (and must be paid for) by a licensed electrical inspector in Kentucky are the stickers shown in the table below.

You may also see a "final inspection pending" sticker when only the rough-in electrical inspection has been completed.

Do I have to down-size a "too big" electrical panel box?

My electrician installed a 16 size main electrical panel box in my home and the inspector says he needs to replace it with a 14, which they don't make anymore. I am having my house renovated and the inspector will not pass our inspection, until we down size the box. What can I do? On 2015-12-18 by joy r -

Reply by Janet Dempsey (mod) - electrical box won't be "too big" but has to be "big enough" for the number of breakers and service amps

I don't understand the sizes in your question but it sounds strange. As long as the circuit breaker size and service ampacity are correct the physical size of the panel wouldn't be a question. Perhaps we a are missing something.

FHA inspector said "wires into the panel need to be covered"

I'm selling my house and FHA has come back and said that the wires going into the panel need to be covered. Do I need to butt the drywall right up to the panel or do I leave a gap? On 2012-12-15 by Carol -

Reply by (mod) - check with local electrical inspector to get the missing details

Carol,

I want to be helpful but frankly am scared and don't make enough money to pay for your house if you have a fire or injury.

I'm also nervous that the FHA advice given may itself be defective or incomplete - and not having seen the home, am flying blind.

IN general, electrical wires are OFTEN exposed at and close to the electrical panel, but the electrical panel itself, by contemporary codes, may be required to be mounted on FRT plywood, regular plywood, or over fire-resistant or other drywall;

Your best bet, to protect both yourself (you do the work, you are responsible if later it's found unsafe or wrong) is to ask your local electrical inspector to take a look and tell you what's needed. It's doubtful that a huge expense is involved.

Take some photos and send them along with what you are told and we may be able to offer more specific advice or help.

Can an electric panel be located in a bathroom?

Can an electrical panel be located in a bathroom? Any specific answer on the site? On 2012-07-31 by Geoff Stewart

Reply byy (mod) -

Goeff, thanks for the question.

No, under the NEC, electrical panels may not be installed in bathrooms (nor in clothes closets).

Can I use a picture frame to cover an electrical panel that has lost its door?

can an eletrical panel that has no door or cover be covered with a picture frame? On 2011-10-12 by bufa -

Reply by (mod) - NO

A picture frame would not make an acceptable electrical panel cover because it lacks the fire rating provided by a metal door. Too there might be technical issues about rapid, ready, easy access.

Reader suggests home inspectors tell clients not to touch them directly if the inspector is getting shocked

It might be a good idea to tell your clients that if you are getting a "charge" from the panel, not to touch you with thier hands as they will get "charged"as well. If alone, well good luck. Oh yeah, tell client to push you away with somrthing made of wood. On 2011-04-28 by ehi -

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Continue reading  at ELECTRIC PANEL AMPACITY or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ELECTRIC PANEL INSPECTION - home
• CHALLENGER ELECTRIC PANELS
• Classified CIRCUIT BREAKER WARNING
• CORROSION in ELECTRICAL PANELS
• DOUBLE TAPPED CIRCUIT BREAKERS
• ELECTRICAL PANEL AGE
• ELECTRIC PANEL AMPACITY
• ELECTRICAL PANEL FUSED NEUTRAL WIRE HAZARDS
• ELECTRIC PANEL WORKING SPACE
• ELECTRICAL DISTRIBUTION PANELS
• FEDERAL PACIFIC FPE HAZARDS
• INSPECT CIRCUIT BREAKERS, FUSES
• MAIN ELECTRICAL DISCONNECT
• MAIN DISCONNECT AMPACITY
• MOISTURE SOURCES in PANELS
• MURRAY CIRCUIT BREAKER HAZARDS
• MURRAY SIEMENS Recall
• PUSHMATIC - BULLDOG PANELS
• REPLACEMENT ELECTRICAL PANELS
• RUST in ELECTRICAL PANELS
• SIEMENS MURRAY Recall
• SPLIT BUS ELECTRICAL PANEL HAZARDS
• SQUARE-D AFCI RECALL 2004
• SQUARE-D COUNTERFEIT BREAKER RECALL
• TEST MAIN BREAKERS & FUSES
• WALKER ELECTRICAL PANELS
• ZINSCO SYLVANIA ELECTRICAL PANELS


• ELECTRIC PANEL INSPECTION SAFETY

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ELECTRIC PANEL INSPECTION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to ELECTRICAL INSPECTION & TESTING

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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