Questions tagged [electrical-panel]

For questions about panelboards (also known as "electrical panels", "circuit breaker panels", "fuse boxes", "distribution boards", "consumer units", or "load centers"). Questions about individual overcurrent protection devices should use [circuit-breaker].

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48
votes
1answer
12k views

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 ...
37
votes
1answer
12k 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 ...
35
votes
4answers
5k 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 ...
28
votes
5answers
383k 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 ...
27
votes
2answers
12k 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? ...
26
votes
3answers
3k 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 ...
25
votes
4answers
140k 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 ...
24
votes
7answers
4k 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 ...
23
votes
13answers
25k 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 ...
23
votes
4answers
9k 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 ...
22
votes
5answers
8k 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 ...
22
votes
13answers
114k 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 ...
21
votes
7answers
5k 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 ...
21
votes
10answers
25k 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 ...
20
votes
2answers
11k 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 ...
19
votes
6answers
9k 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 ...
19
votes
6answers
3k 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 (...
17
votes
5answers
7k 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....
15
votes
4answers
6k 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/...
15
votes
3answers
4k 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" ...
15
votes
3answers
5k 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 ...
14
votes
6answers
21k 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'...
14
votes
4answers
5k 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 ...
14
votes
1answer
2k 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 ...
14
votes
5answers
3k 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. ...
13
votes
3answers
2k 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 ...
13
votes
1answer
4k 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. ...
12
votes
4answers
3k 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 ...
12
votes
5answers
2k 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 ...
12
votes
3answers
6k 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 ...
11
votes
8answers
166k views

Do the breaker amp readings sum up to dictate my current panels total / possible amperage?

So I know practically nothing about houses having rented for many years, just bought a house and was told by my inspector the panel is only a 70 amp panel and will need to be upgraded before I go to ...
10
votes
3answers
1k views

Are the grounds and neutrals in this electrical subpanel reversed?

I would appreciate your feed back to help me understand the logic behind Bonding the Neutral and Isolating Ground as shown in the attached pics. Subject sub panel is dedicated to one of four ...
10
votes
2answers
2k views

Can I run an underground wire to a shed on blocks?

I have a 12'x16' shed which has been leveled using concrete blocks but otherwise sits on the grass/dirt. It's about 100' from the house. I live in Georgia. I'd love to add some lights and outlets ...
10
votes
2answers
1k views

New house generator AC breaker tripping

I have been in our new house less than 1 year. Yesterday we had a a prolong power outage so I decided to test the generator I got for hurricane season to the house existing generator inlet. I turned ...
10
votes
2answers
4k views

Tandem breaker needs both thrown to break circuit. Incorrectly wired?

I have a tandem circuit breaker in my main breaker box with two 20 amp breakers. To turn off power my wife's office, I need to throw both breakers. I can throw either one and as long as the other is ...
10
votes
1answer
2k views

What is this metal thing on my circuit breaker

Just bought a condo and one of the breakers in it has this metal thingy on it. What is it? What is it for?
10
votes
3answers
102k views

Is it code-legal to have a circuit breaker box within a storage room?

I am currently in the process of planning a room remodel to convert an existing bedroom into a home office and storage room. One thing that makes this conversion a little bit tricky, is the existence ...
9
votes
6answers
6k views

Using a heater and toaster oven trips the breaker. Can an electrician fix this?

Using a heater and a toaster oven together, both about 1500w each, trips the breaker. It seems both are on the same circuit. Moving either appliance to a different location is not really an option. ...
9
votes
9answers
6k views

My 240 volt outlet seems to be delivering 219 volts

I am seeking help with my confusion about where my problem lies and what to do next. I had a home renovation and got new appliances and upgraded circuit box two plus years ago. But not the "heavy ...
9
votes
5answers
2k views

20 amp circuit breaker failed to trip

I had an electrician install a dedicated 20 amp GFCI duplex outlet and 20 amp circuit breaker (both customer supplied) two years ago. The outlet is directly below the panel box. Just this month, I ...
9
votes
5answers
4k views

What type of cable should I run to future-proof an outlet for an air conditioner?

Our new house is still under construction by a standard builder. After the home is finished, I will be installing a small mini split ductless AC system for a home office that will get much warmer than ...
9
votes
2answers
5k views

Should there be a screw securing the main breaker in my electrical panel?

I'm trying to find the breaker to switch off a light fixture to install ceiling fan. I've tried all but the ones dedicated to ac, furnace, dryer etc. I decided to switch off the main and encountered ...
9
votes
1answer
2k views

Is some asymmetry in a breaker box normal? What about neutral to ground having voltage?

So, next in my quest to evaluate the health of my new home's electrical system, and call in professionals if needed, was some voltage checking of the panels/outlets around the house. What I have is a ...
9
votes
6answers
9k views

Are power outlets in a home out of phase with each other?

I'm working on a science project and there's one aspect of home wiring I need to find out (don't worry, I'm not messing with wiring - this is all on paper). Since 120V outlets in a home can be wired ...
9
votes
2answers
4k views

Add grounding to a 9th floor apartment in country with no electric code at all

I live in a 9th floor 1940s-era apartment in a country with no electrical code and no professional licensing for electricians. My 'electrician,' such as he is, is a security guard who does wiring on ...
9
votes
2answers
3k views

Large voltage swing on incoming main hot line- definitely outside?

So for much of last fall, I had an issue of flickering lights in my house (half of the house seemed to flicker in unison). Back in December, I called the electric company, who came out, and claimed ...
8
votes
2answers
2k views

If you can use duplex breakers, is there ever a reason not to?

In general, when circuits need AFCI protection (or GFCI protection if you don't feed everything through GFCI receptacles), you can't use duplex breakers, since there's not enough room for the ...
8
votes
6answers
56k views

Can I connect a 100A subpanel to a 100A main panel?

I currently have a 100amp main service box but it is all full and some are even doubled up.I'm wondering if i can hook up a 100amp subpanel off of it? If so what size wire to go with? It would be on ...
8
votes
3answers
3k views

Convert GE Load Center to main breaker

I'm looking to add central A/C to my 1970s era home. The electric panel is a GE Load Center, 125 Amp max. It's basically "full" with no space for additional breakers. The bids for the electric panel "...

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