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Questions tagged [electrical-panel]

Panelboards, also known as "electrical panels", "circuit breaker panels", "fuse boxes", "distribution boards", "consumer units", or "load centers". Remember to provide your location. Include photographs of the existing equipment or plans. Questions about individual overcurrent devices (breakers or fuses) should use the [circuit-breaker] tag.

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55 votes
1 answer
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Half my power out, but firing up an appliance turns it back on

Hoping for some much needed help. The other day my lights flickered and half the power and outlets went out in my home. They have gone and off periodically since then, spontaneously shutting off at ...
Jimmy Vincent's user avatar
43 votes
2 answers
27k views

What is a tandem breaker (aka duplex, cheater, twin, double-stuff, etc.)?

I keep hearing about tandem breakers, and how they won't work with 240V loads and how they should never be used for a multi-wire branch circuit. Aside from those issues... What is a tandem breaker? ...
Harper - Reinstate Monica's user avatar
42 votes
4 answers
27k views

Why is my voltage dropping with load and why is current flowing on my ground wire?

I am not an electrician, but I've been researching a lot recently to try and figure out why my system is behaving so strangely. Main problem: Lights flickering, sometimes quite severely, and ...
Sasha Aickin's user avatar
41 votes
2 answers
14k views

How did a circuit that was shut off at the breaker almost kill me?

I just had a near-disaster while trying to install new smoke detectors. My house has AC hardwire connections for the smoke detectors. I wasn't sure which circuit the smoke detector AC connection was ...
Kevin's user avatar
  • 1,457
38 votes
2 answers
13k views

What on earth is this small wall-mounted computer?

I live in a rented apartment, and there is this little plastic box on the wall that I had been ignoring. Here is what it looks like: There are no markings or holes on the casing. I got curious and ...
mostsquares's user avatar
32 votes
4 answers
153k views

Should all Federal Pacific panels be replaced?

I understand that Federal Panel Stab Lok breakers have the potential for becoming stuck, overheating, and starting fires. My home has a Federal Pacific panel but no outward markings of being a Stab ...
STW's user avatar
  • 736
32 votes
5 answers
497k views

Is it ok to have mixed grounds and neutrals on bars in a breaker box?

So to continue my line of electrical questioning (and perhaps narrow down my flickering light problem), I took a look through the two panels in this house. There is a 200amp main service in the ...
MarkD's user avatar
  • 5,125
29 votes
7 answers
9k views

How can I add an ammeter and/or voltmeter to my home breaker panel?

In my professional life, I work in datacenters and all of our PDUs have ammeter displays on them. Of course they do: we always want to know how many amps a PDU is using. But in my house, nobody has ...
user227963's user avatar
  • 1,078
29 votes
3 answers
11k views

How did my ground and neutral become energized by a short in the buried main line?

Long post, because I'm not sure what information is critical. The ultimate question is what, if anything, I need to do to ensure there are no hazardous conditions in my home. Friday night, the ...
Larry's user avatar
  • 407
28 votes
4 answers
6k views

Why is there a jumper between these circuit breakers?

I was replacing defective/broken outlets in my folks' house this week, in preparation to sell it. So I went to the power panel and hit the appropriate breaker for the area I was working in. No problem ...
William Brown's user avatar
25 votes
7 answers
19k views

Panel breakers are alternately 90 V and 140 V

Everything in the house is acting up. The fridge has melted ice, the radio is acting strange, etc. I multimetered the panel box and each breaker is either 90 V or 140 V alternately. I have a plan to ...
drmadef's user avatar
  • 259
25 votes
13 answers
147k views

What is simplest strategy to map circuits to breakers in the panel?

My breaker box is very poorly labeled and I want to figure out which circuits may have overloaded (or close to it) and which could reasonably handle a little more. In the past I have just tried ...
auujay's user avatar
  • 5,285
25 votes
4 answers
11k views

Why would two circuit breakers be connected inside the service panel?

I was trying to locate the circuit breaker for an outlet in my garage and found a truly baffling setup. Two breakers control the same outlet (both plugs). After some head scratching, I opened the ...
John Miele's user avatar
24 votes
10 answers
71k views

My inflatable hot tub says "don't use with an extension cord"... but can I?

Sadly they don't explain WHY not to use it with an extension cord. I wonder if it's to do with the risk of having such connections outside in the elements? The cord it comes with is 7m long, and ...
Codemonkey's user avatar
24 votes
6 answers
17k views

Can a 40amp breaker be used safely and without issue with a 40amp device on 6AWG wire?

We are installing a Cooktop that calls for a 40amp circuit. I was given 6AWG wire (instead of the 8AWG wire I asked for) by mistake. The electrician saw the 6AWG wire (that I had already run) and used ...
Steve Sensabaugh's user avatar
24 votes
13 answers
50k views

What items in a house can potentially be damaged by shutting them off at the circuit breaker?

Are there certain items in a house (anything from a computer to a furnace) that can be damaged by shutting off its circuit at the electrical panel? If so, must one avoid turning off that circuit at ...
Fil's user avatar
  • 811
23 votes
5 answers
3k views

subpanel breaker tripped as well as main breaker - should I be concerned?

All... My garage had only one outlet so I extended it using surface raceways. Like a dummy, I did not turn off the breaker when I started the installation of the raceway. "I know what I'm doing ...
Clint's user avatar
  • 361
22 votes
6 answers
22k views

Weird Power Outage in Certain Rooms- Condominium

Half of the Condo I rent is losing power sporadically, sometimes for minutes other times for hours. We have power loss to our kitchen lights, microwave, outlet above dishwasher, the dishwasher, entire ...
Ashley's user avatar
  • 229
22 votes
2 answers
18k views

What danger/code violation is oversized breakers?

I just got the results of a home inspection where they claim there is mismatched breakers and wires in my electrical panel. Specifically, the range (40A breaker) and heat pump (50A). He claims the ...
kinar's user avatar
  • 1,089
22 votes
3 answers
4k views

Why are all the neutral wires in a sub panel burnt or melted?

My barn had a small (6-space) main lug sub panel with four 20A 120V breakers and one 20A 240V breaker. The panel itself was protected by a 50A 240V breaker in the main service panel. It was wired up ...
Kurt Granroth's user avatar
21 votes
6 answers
4k views

How can I calculate my anticipated peak current load?

Preamble This question takes place in Japan. In Japan, domestic electrical service is metered, but there is also a monthly fee that increases with larger service capacity. Units are wired for (...
steros's user avatar
  • 319
19 votes
5 answers
11k views

What type of cable should I bury for a small utility shed?

I'm putting a 8x16 utility shed in my back yard. It will be 100 ft from the service panel. I want to run the supply line under ground. There will be one 4ft fluorescent light and two 120V receptacles....
user avatar
17 votes
3 answers
18k views

What is the difference between a "handle tie" and "common trip" in circuit breakers?

This image shows a quad-breaker with handle ties. Image borrowed from this DIY question One of the comments noted that despite the "handle ties", this is not a "common trip" ...
FreeMan's user avatar
  • 47.4k
17 votes
3 answers
5k views

Bosch Drawer Microwave causes ARC Faults

I have a brand new Bosch Microwave (model: hmd8451uc) installed as the only device on the entire circuit. Anytime I use the Microwave on this circuit, it triggers the breaker's ARC Fault. Breaker (...
Arian F's user avatar
  • 371
17 votes
2 answers
7k views

Considering doing a 100A sub panel install on my own. Any guidance would be much appreciated

My background: I am an Electrical Engineer by schooling and I'm a pretty handy guy overall. I have been working on and around just about everything since as long as I can remember. I have a good grasp ...
aveach's user avatar
  • 201
16 votes
2 answers
6k views

If my 240v cooktop does not have a neutral, is it safe just to cap the neutral and leave it? [duplicate]

I bought a cooktop which has 3 wires: Black Red Green The wiring in my home is 4 wires: Black Red White Bare I saw the instruction for 3-wire to 4-wire connection, it states to leave the white ...
movila's user avatar
  • 273
15 votes
4 answers
8k views

Loss of power when I remove item from the outlet

I have this unusual electrical issue in our master bedroom. I was wondering if anyone else has experienced this. We have this $3 LED night light in our bedroom and when we take it out, the power/...
Vipul Mistry's user avatar
15 votes
4 answers
4k views

I installed a new outlet and tripped the whole power panel... Does a 30 amp circuit need special outlets?

So... I tried swapping two outlets in my kitchen, and tripped the entire power panel! The old outlets were wired with FOUR wires: red, black, white, bare. I wired the new outlets using the same ...
steeveedee's user avatar
15 votes
3 answers
2k views

How should I power a shed before the house is built?

I want to bring power in to an undeveloped lot, where the first thing I want to build is a shed/shop. This will be the main base of operations while I begin constructing the main house. Since I will ...
nscheens's user avatar
  • 153
14 votes
7 answers
40k views

Breakers loose in main panel, does whole panel need to be replaced?

I went on a breaker flipping binge the other day because the panel at my house wasn't labeled and I had a doorbell transformer to replace. After I got the doorbell finished I realized the fridge wasn'...
Hart CO's user avatar
  • 312
14 votes
5 answers
16k views

Are these pigtails inside the panel and outside a junction box allowed?

I am concerned about a newer electrical panel's installation, where one of the older load wires, at the main electrical panel, appear to be shorter in length, appear not reaching the desired circuit ...
H1991's user avatar
  • 707
14 votes
3 answers
4k views

Do I need to replace my electric panel to eliminate tandem breakers?

I am looking into installing an electric car charger. I called a few electricians to get a quote. My main panel is full, but there is an existing 50 amp breaker for an electric cooking range which is ...
sp1984's user avatar
  • 171
14 votes
2 answers
3k views

Is electrical panel safe after arc flash?

I was trying to install CT clamps on the service wires to my center fed main electrical panel. I used pliers and by mistake torn a bit the insulation on one conductor while the pliers were touching ...
user162793's user avatar
14 votes
1 answer
5k views

Safety hook on double pole circuit breakers

My home was built two years ago, so I would expect everything to have been done up to code. The problem is that I don't know what the metal ring in this photo is. It loops over the double pole circuit ...
mh00h's user avatar
  • 243
14 votes
1 answer
5k views

Why are adjacent breakers for unrelated circuits ganged?

I'm looking at electric panels in some newer residences and seeing something confusing: Circuit breakers that are adjacent to each other, but that cover unrelated circuits, are ganged, as shown below. ...
feetwet's user avatar
  • 2,647
14 votes
4 answers
9k views

why is a service neutral grounded but not the subpanel-neutral?

I know it's code (refer to NEC 250.24(A)5 and 250.32), but I don't understand why you can't use a bonding jumper to connect the ground bus and neutral bus in the subpanel? I've been told it's because ...
Ben Welborn's user avatar
  • 6,212
14 votes
5 answers
4k views

I tripped a 20amp breaker but didn't feel a shock - why?

I was stripping a hot ungrounded conductor while a 20A breaker was on by accident. When my wire strippers pierced the sheathing, a large spark blew out and tripped a breaker, but yet I felt nothing. ...
Tony DiNitto's user avatar
13 votes
3 answers
3k views

Running Service to Outbuilding

We just built a house and wanted to run 400 amp service to the house to keep options open down the road, but I fear my contractor didn't account for my future plans and did what easiest vs what I ...
cvgnew's user avatar
  • 139
13 votes
3 answers
6k views

Is it okay/safe to load a circuit breaker to 90% of its amperage rating?

To charge my EV I have a Level 2 Emporia EV Charging station (aka "EVSE") that is capable of outputting a maximum of 40 amps when using its included NEMA 14-50 plug on the supply side. ...
Richard B's user avatar
  • 133
13 votes
5 answers
4k views

Square D Homeline AFCI breakers trip for all appliances

I'm trying to install AFCI breakers on my kitchen SABCs (2x 20A circuits), in my Square D Homeline panel. Unfortunately, the breakers trip whenever I try to do anything useful on those circuits. I've ...
peter's user avatar
  • 1,498
13 votes
2 answers
5k views

Why did my water heater wire burn up?

Here is a picture of the damage. Thank goodness they're was no fire. We had our breaker panel replaced today. I don't know if that's related or just coincidence. Tonight about 8:30pm while getting ...
JBurt's user avatar
  • 367
13 votes
6 answers
20k views

Why aren't AFCI breakers required for bathrooms/lavatories?

Why doesn't NEC require AFCI breakers for bathrooms/lavatories? Is there a good reason NOT to install AFCI protection on a 15A/20A 120V bathroom outlet? (I.e., use GFCI only.)
RJ539's user avatar
  • 141
12 votes
4 answers
11k views

Can I use a single 20A circuit for two bathrooms?

Can I put two bathrooms on one 20amp breaker for the respective outlets or do I need a separate 20amp circuit for each bathroom? I am running out of panel space in my subpanel otherwise I would just ...
Ron Hutchins's user avatar
12 votes
3 answers
4k views

Electricity coming from panel is not right

After a recent power outage i have serious power issues in my garage. With no load, i get solid 123vac from both channels in the box and a solid 240vac across both legs. As soon as i apply a load one ...
wsnbh's user avatar
  • 123
12 votes
2 answers
3k views

Old subpanel has dual 60A breaker feeding lighting

We've inherited an old house, and the original panel for the house seems to be a subpanel to the new service panel that primarily has electric baseboard heating, and two 20A circuits of receptacles in ...
Dave X's user avatar
  • 418
12 votes
4 answers
4k views

What is this 110/24V 60Hz transformer in the breaker room for?

My friend sent me a photograph of this transformer, which is installed above the main breaker panel, with leads running from the panel into the transformer. The stamped labels read PRI. Volts: 110 ...
msanford's user avatar
  • 629
12 votes
5 answers
14k views

Are two wires coming out of the same circuit breaker safe?

There are two wires coming out of two of my circuit breakers in my electrical panel. I am thinking the previous owner of the house stuck these two wires in there because the panel was full and they ...
CSR's user avatar
  • 129
12 votes
4 answers
2k views

How can you spot MWBC's (multi-wire branch circuits) in an electrical panel [duplicate]

Is there a definitive way to know whether MWBCs are present (or not) in an electrical panel? That is, are there multi-wire branch circuits? Can one look at the connections at the panel to see a clear ...
user2330237's user avatar
12 votes
2 answers
1k views

Am I correctly replacing two two-pole breakers with a quadraplex breaker?

I am replacing the top two of those two pole breakers in the top left (green) with one quadplex with common trip model EATON BQC220220. Is the attached wiring diagram right(just follow the dots color ...
John Whicker's user avatar

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