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.

Residential Electrical Panel Cover Inspection and Special Safety Hazards - Look before you touch!

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.

In our photo, the client is pointing to a small rust spot near the corner of the electrical panel door. Rust and corrosion may have made the electrical panel or its components unsafe, including having corroded circuit breakers such that a breaker may fail to trip off in response to an over-current, or may fail to turn electrical power off internally even when the toggle switch is in the OFF position.

Article contents

• ELECTRICAL PANEL COVER
• CIRCUIT WIRING AMPS FUSING
• PROBLEM-BRAND ELECTRICAL PANELS
• ELECTRICAL PANEL FUSED NEUTRAL WIRE HAZARDS
• ELECTRICAL PANEL LOCATION
• FUSES vs CIRCUIT BREAKERS
• MAIN DISCONNECT INSPECTION
• OTHER ELECTRICAL PANEL DEFECTS

Before Touching or Opening the Electrical Panel for Inspection

• Look (and test? before touching, open door, look again (rust, burns, gaps, unsafe stance)
• Block client from touching equipment
• May be unsafe to remove upper cover of combination panels (service main at top)
• Sheet metal screw shorts, shocks, fires
• Swing-out covers can pinch wires
• Loose circuit breakers or breakers held in place by the pressure of the electrical panel cover can come loose from their mounting bus, causing a dangerous or even fatal arc explosion when the electrical panel cover or faceplate is removed.

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:

• 14 gauge - 15Amps
• 12 gauge - 20 Amps
• 10 gauge - 30 Amps
• 8 gauge - 40 Amps

Exceptions to these wire sizes and fusing occur for special circumstances such as air conditioners whose motors produce a brief current surge during startup.

• Aluminum electrical branch circuit wiring size guide:
  
  Modern electrical wiring systems do not use single strand solid conductor aluminum branch circuit wires such as for electric lights or electrical receptacles.
  
  Currently (since the 1970's), aluminum electrical wiring is used only in the form of multi-strand on single-use circuits such as found on appliances like a water heater, air conditioner, or an electric range.
  
  Keep in mind that where using aluminum wire in those applications, for a given required circuit ampacity, you'll use the next size larger (gauge) aluminum wire than you would if the wiring were copper.
• Solid conductor aluminum branch circuit wiring is unsafe, a fire hazard, and requires repair -
  
  see ALUMINUM WIRING HAZARDS & REPAIRS - home

Problem-Brand Electrical Panels

• CHALLENGER ELECTRIC PANELS replacement breakers/panels
• CLASSIFIED CIRCUIT BREAKER WARNING
• Federal Pacific Electric Stab-Lok breaker panels -
  
  see FEDERAL PACIFIC FPE HAZARDS
• PUSHMATIC - BULLDOG PANELS
• SQUARE-D COUNTERFEIT BREAKER RECALL
• ZINSCO / SYLVANIA HAZARDS
• Other problem-prone panels or breakers (more research needed)

Electrical Panel Location Defects

• Main Electrical Switch & Panel Location:
  
  should not be located in these prohibited spaces:
  
  Prohibited electrical panel locations: Bathroom, clothes closet, kitchen cabinets, stairwells (same issues as for service disconnect), above steps or stairways
  
  Example detailed NEC citations:
  
  NEC 230.70(A)(2) & - NEC 240.24D ... not in a bathroom [as defined in NEC 210-8]
  
  NEC 240.24D Overcurrent devices shall not be located in the vicinity of easily ignitable materials, such as a clothes closet.
  
  Accepted electrical panel Locations:
  
  The US NEC does not prohibit locating an electrical panel on a stairway landing nor are there prohibitions against locating the panel in a bedroom, basement, garage, or utility closet (provided there is sufficient working space), nor is there a prohibition of location of the panel in hallways or laundry areas (though other working-space clearance details must be observed).
• Electrical Panel height:
  
  Should be at eye level, easily accessible, 3 ft. clearance
  
  See details at ELECTRIC PANEL WORKING SPACE
• Sub-Panel locations:
  
  may be located almost anywhere (still some Sub panels are improper by location or by working space requirements as above).
• Finding hidden sub panels:
  
  Look for feeder-breaker/fuse or wires leaving main

Relative Electrical Safety of Fuses versus Circuit Breakers

• Fuses more reliable to "blow" -
  
  Not mechanical BUT easier to over-fuse (reduce with S-type retro)
• Breakers more convenient to reset
  
  the breakers can be tested without having to then replace the safety device - less likely to be over-fused (but over fusing still happens - compare wire gauge to breaker ampacity)

Electrical Panel Main Disconnect Inspection - Do you Pull the Main Fuse or Test the Main Breaker?

• may be necessary to get some panel covers off
• may be unsafe or may not want to shut power off to building
• ask occupant/owner before killing power
• report limitations to inspection
• re-set accidentally tripped breakers and leave note

Other Electrical Panel Defects Discoverable by Visual Inspection

• Obsolete and/or ELECTRICAL PANEL FUSED NEUTRAL WIRE HAZARDS
• Damaged panel/components
• Loose panel
• Inappropriate support material
• Unprotected panel openings/knockouts
• Undersized panel - physical size/crowded
• Overheating - look at mains, breakers, bus, neutrals, wires
• Rust or water - look for rust, corrosion, overheating, subtle spots, suspect hidden damage to bus or breakers, look for water trace marks on entering SEC
• circuits not labeled
• panel overcrowded
• poor access to panel
• panel upside down or switches on in down position (obsolete)
• Panel used-with and not suitable for AL wiring
• Uncapped wires loose in the electrical panel, possibly improperly abandoned circuits

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, Aug 2018.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-02-03 by Inspectapedia Com Moderator - need to move electrical panel out of bathroom

@J,

I'm not sure that amounts to a complete rewiring of the house. Typically what happens is the electrician installs the new panel and routes all of the circuit wires from their old panel location to the new panel and back.

Essentially the old panel becomes a giant junction box. That's the location question that you want your electrical inspector to approve.

On 2022-02-02 by J

Thanks for your reply. I really appreciate the input. Safety is definitely our number one priority. I fully understand the reason why the electrical panel can’t stay in the bathroom. Right now we’re in the thinking stage so we haven’t reached out to any contractors. We just like to have a general idea of what we’re dealing with before starting that process.

Regarding your question as to why moving the panel (without using the current one as a junction) would require a complete rework of the wiring I’ve attached a couple photos of the current box. Hopefully I’m wrong since moving it to another location in the basement would be best.

Using the current panel as a junction & putting a new one upstairs seems like a good option. I’ll reach out to our local code department to see if that’s acceptable. One problem I noticed after I posted is that the only available wall in the kitchen may not work.

We live in a 1950s rowhouse & that wall is drywall on furring strips on concrete block and there’s no space to build it out. The only other location seems to be the landing to the basement stairs but on further reading it looks like that’s not an option. Does the code have distance limits?

On 2022-02-02 by Inspectapedia Com Moderator - two choices - either move the panel or move the bathroom?

@J,

I appreciate the dilemma that you raise and at the same time I expect that we both take seriously the risk of death by electrocution when an electrical panel is in bathroom - the reason behind the building code requirements that you cite.

I suggest taking the question to

1. your local building department to see what alternatives the inspector considers acceptable. I note that simply extending wiring to move the panel upstairs to the kitchen might leave an enclosed electrical junction box that must remain accessible in the present panel location, but that might be acceptable to your electrical inspector.

2. your licensed electrician who can also suggest options for moving the panel, perhaps upstairs or perhaps elsewhere in the basement.

Finally you might ask for clarification: I don't understand why moving an electrical panel requires re-doing all of the home's wiring. That sound rather extensive.

On 2022-02-02 by J

My husband & I are starting to plan a full renovation of a 550sf basement. The electrical panel is located in a corner of the basement in the bathroom which is also where the main waste & water lines enter the house. To comply with current code it appears we have two choices—either move the panel or move the bathroom.

Moving the panel will require redoing the wiring for much/all of the house. Moving the bathroom will require ripping up the concrete slab to relocate the waste line. Also, for our needs, the current location of the bath is optimal so we really want to keep it where it is.

Our house is small & we don’t want to use valuable space for a separate enclosure (2.5ft x 3ft?) for the panel. Are there other options/workarounds? FYI—above the panel/bathroom is our kitchen as well as the landing to the basement stairwell. Thank you

On 2021-03-12 by danjoefriedman (mod) - "Rule of 6" applies for dedicated overcurrent protection

@David Betts,

Okay so if I understand you you have a 200 amp sub panel that is quite remote or distant from the panel that feeds it is protected or the feeder line to it is protected in the main panel but there's no main switch of the sub panel but because the sub panel has fewer than six switches the electrical inspector quite likely would not have required a main disconnect there

On 2021-03-12 by David Betts

@danjoefriedman, The switch is neither "at nor in." The only overcurrent protection for the garage sub-panel is the 200-amp main disconnect at the main service panel (located outside the house). I just find this weird. The 6-hand rule has not been violated but the electrician provided no means of isolating the subpanel.

On 2021-03-11 by danjoefriedman (mod)

@David Betts,

the panel does have to have a dedicated main switch but the switch can be at the panel, it doesn't have to be in the panel

On 2021-03-11 by David Betts

@danjoefriedman, Thank you. Even if the 6-hand rule is not violated, something about this arrangement bothers me but I can't put my finger on it. I guess it seems cheap. I don't like the idea of each panel not having a dedicated overcurrent device.

On 2021-03-09 by danjoefriedman (mod)

@David Betts,

The "rule of 6" applies: if there is no main cutoff switch close to that 200A panel and if the panel has more than 6 circuit breakers you'd expect local code officials to dis-allow it as unsafe.

If in the main electrical panel, the disconnect breaker that supplies the 200A sub panel is close enough (perhaps a few feet - local codes vary), and is visible and readily accessible then your local inspector may be satisfied.

I share Carson Dunlop's view of the case you describe.

But the "rule of 6" is a guideline, enforced by local code officials, but may not be explicit in your electrical code.

Building codes try but cannot anticipate every unsafe or goofy thing people might do.

On 2021-03-09 by David Betts

On some houses in North Carolina, I am seeing 200 amp sub-panels without dedicated overcurrent protection in the sub-panel or in the main panel either (other than the main disconnect switch). What do you think about this arrangement? Power to the whole house has to be disconnected in order to isolate the sub-panel.

Does a 200 amp main disconnect switch in the main panel suffice as overcurrent protection for a 200-amp sub-panel? Carson & Dunlop seems to have a low opinion of this type of arrangement based on one of their diagrams, but I cannot find an NEC rule that specifically prohibits it.

On 2020-12-30 by danjoefriedman (mod) - ensure adequate working space around electrical panel

Stephen

I would build whatever space or shelter is needed to give proper working space for the panel and the transfer switch. There is good reason for that working space requirement and I worry that shoehorning it in to an already too small area is in fact unsafe.

Am I correct that the cost of making space is probably small compared with the total cost of your generator, transfer switch, and electrical work?

On 2020-12-30 by Stephen

I have a 1980's, 400 amp service to which I wish to add a 400 amp transfer switch for a 70kw generator. Although "grandfathered in", I do not have the necessary 36" (have 24") working clearance in front of the main panel which is exterior to the neighbors building.

My electrical contractor says that I do not need a 36" working clearance for the ATS as it would not require any service while energized. Otherwise, the generator would be de-energized at its source, as well as the main power. The building department says that the ATS requires a 36" frontal clearance.

There is no alternative location for installation. Any suggestions. I would assume that this is an issue that comes up, occasionally.

On 2020-05-22 by danjoefriedman (mod)

Anon

I'm not sure that the manufacture date is encoded in an Eaton electrical panel, though there is a date code on some circuit breakers.

Give Eaton customer service a call and let me know what you're told

877-etn-care (877-386-2273)

On 2020-05-21 by Anonymous

How can I find out when this was manufactured
Eaton BR612L125FDGP

Made in USA

Item:

0347166
Cat:

BR612L125FDGP
Mfr:

Eaton
UPC:

786676002080

On 2020-02-24 - by (mod) - don't put the electrical panel in a closet, kitchen cabinet, bathroom nor along the stairs

Al

No.

A quick search of this website for "electrical panel in closet" finds ELECTRICAL DISTRIBUTION PANELS

where we read:

Electrical Panel Location Defects

Mains: Not in: bathroom, clothes closet, kitchen cabinets, stairwells (landing may be OK) (same as service disconnect)

Also if an electrical panel or "fuse box" is in a closet there would be an electrical panel working-distance issue:
A quick search of InspectApedia.com using the search box just above, to look for "Electrical panel clearance distances" finds

ELECTRIC PANEL WORKING SPACE which explains the required working distances or clearances around an electrical panel, its height from the floor, etc.

On 2020-02-24 by al harden - can the fuse box be located in closet?

can the fuse box be located in closet

On 2018-10-22 - by (mod) - don't put the electrical panel in a closet

I'm not sure you want to put an electrical panel in a closet where access maybe two limited and unsafe and a code violation.

On 2018-10-21 by Luis Gonzalez

I need to movie an outside service panel corroded by age and sea air approximately 15 feet on the same wall that receives the service,

to a new panel inside a closet that’s close to a water heater

and use it to ground a few key outlets in the house—bathroom, kitchen, computer and living room entertainment center, for GFCI and surge protection. Is this the route to take, or is burying a grounding rod and ground the whole service panel?

That means running new conduit throughout the house. The current circuits run through different rooms but it could be used to protect other outlets on the same run with a GFCI outlet and add some grounded protection where none exist.

On 2016-12-08 - by (mod) - requirement for conduit or for using armored cable electrical wire

The conduit requirement (or flexible armored cable) depends on where in NY you live, e.g. in NYC NMC (plastic) wiring is not used.

Important is the overcurrent protection at the source-end of the wire.

On 2016-12-08 by Dave V

I live in NY state and I'm running 100 amp wiring a detached garage from my main box in the house. The wiring will travel through the basement ceiling/first floor joists. Does the wire have to be in conduit? It is in conduit once out of the house and underground to the garage.
Thanks,
Dave

Jeff: see Bryant breaker performance data

at CIRCUIT BREAKER FAILURE RATES

On 2015-10-16 by Jeff

Where is the problem with Bryant Panels?

Question:

(Nov 15, 2012) Leo Duprey said:
I have a 200 amp main. How many and at what sizes of subpanels can I install from this main?(June 1, 2014)

Steve Pettifer said:
I have a 100 amp panel and when I turn on a breaker it reduces the voltage on one buss and increases the voltage on the other buss. I have checked all I can and even installed a new ground. How can that happen?

Reply:

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.

Question: 50 volts on one buss and 190 on the other.

(June 1, 2014) Anonymous said:
I had 225 volts on a 15 amp.
The last thing I tried was a 15 amp electric heater.

That gave me 50 volts on one buss and 190 on the other.
This is a sub panel but I have replaced the 100 amp in the main just in case.
I am checking voltage from each of the buss to the common buss.

Reply:

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

inspectapedia.com/electric/Voltage_Measurement.php

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:
Starting to look like a break in the feed from main panel to sub panel.

Reply

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:
What does open ground means

Reply:

Raul

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:

What is the difference between a 8 space 16 circuit panel and a 16 space 16 circuit panel?

Why would I choose one type over the other? (for what applications and/or their respective limitations)

Reply:

I doubt that vendors are meticulous about terminology, but sometimes "space" means there is a spot to plug in a circuit breaker - the panel is unpopulated; while "circuit" may mean that a circuit breaker is included.

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:
Where do you get your list for problem electrical panels?

Reply:

Mike:

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 leapt 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:
I have a strange measurement- with the main breaker OFF and all other panel breakers OFF if I measure between the HOT side of the main breaker and the NEUTRAL bus bar I get 30vac- ideas please

Reply:

Larry

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.

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Continue reading  at ELECTRICAL PANEL COVER SCREWS and warnings about removing and replacing panel covers, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ELECTRICAL CIRCUIT ID, MAP & LABEL
• ELECTRICAL DISTRIBUTION PANELS - common defects found by visual inspection
• ELECTRICAL PANEL AGE
• ELECTRIC PANEL AMPACITY
• ELECTRICAL PANEL COVER SCREWS
• ELECTRIC PANEL INSPECTION - home
• ELECTRIC PANEL WORKING SPACE
• GROUND SYSTEM INSPECTION - home
• SAFETY for ELECTRICAL INSPECTORS - home
• SERVICE ENTRY WIRING & AMPACITY - home

Suggested citation for this web page

ELECTRICAL DISTRIBUTION PANELS 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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