Distribution and use of electricity throughout the home. Electrical standards vary greatly worldwide, so providing your location in your question or your profile helps ensure you get answers that are relevant to you. Posting photographs of wiring junctions or drawing a wiring diagram and posting ...

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4answers
34k views

Why are homes wired using solid wire rather than stranded?

If stranded wire can carry more power for a given wire gauge, why are homes typically wired using solid? If solid wire is less expensive to make, that provides a compelling reason why solid is used, ...
14
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1answer
2k views

Is this a fire hazard?

I was going to change a light switch and repair some wall damage. When I started opening up the wall above the switch, I saw the electrical wire clamped to the stud. I noticed black marks around it. ...
14
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4answers
63k views

Which Kitchen outlets do NOT need GFCI?

I have the 2 circuits in the kitchen with GFCI outlets, but I'm not quite sure which other ones do NOT need GFCI. Other circuits in the kitchen include Microwave, Fridge, and Dishwasher. It makes ...
14
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3answers
2k views

Can I safely use a switch rated for “1A at 125V” with 240V, assuming I stay below 125W?

I recently purchased a foot switch for a standing lamp. The switch is rated for 1A at 125V. I would like to use this switch with a low energy lamp (typically 10W or below) but with a 240V supply. Is ...
14
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3answers
8k views

Is there a device that will allow a bathroom fan to run for 5 minutes after it is switched off?

There is one switch that controls the lights and fan in the bathroom. Users turn the light/fan on when they enter, and off when they leave. I'd like for the bathroom fan to run for a time after they ...
14
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5answers
121k views

What's the standard height for an outlet?

I am installing outlets in my patio room. What is the standard height recommended above the ground for these to be installed?
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4answers
58k views

I have a 3-pronged receptacle but no ground wire connected to it. Is this ok?

I removed the plates from outlets to paint walls and noticed that some of my electric boxes have ground wires connected to outlets while others do not have a green wire at all. Is this ok? I know ...
13
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6answers
87k views

Can I backfeed a portable generator into my house's electrical system?

Is there a safe way to power my house using a portable generator? The power rating for the generator is 6kW, and I want to run my electric water heater (4.5kW) and my refrigerator (0.5kW) and possibly ...
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4answers
40k views

When to use holes instead of side terminals to wire an outlet

This question comes from Shirlock's comment on this GFCI wiring question. When and why should you use the holes on the back of an outlet rather than the side terminals? I always assumed the holes on ...
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3answers
2k views

How do I install this lamp on my ceiling?

I'm a big time novice but determined not to hire an electrician for what is probably a simple job. This is embarrassing, I think. Here is an exposed light fixture that I have in my attic I want to ...
13
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4answers
80k views

How do I properly wire GFCI outlets in parallel?

I have two countertop outlets in my kitchen that I am in the process of replacing with new, GFCI-protected outlets. These two outlets are on a circuit together, and they are the only loads on that ...
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2answers
5k views

How do I join two cables outside so that they're safe and kept dry?

I have a new pond with a pump but the cable on the pump is far too short. I have some similar cable which will do the job to extend the length. My only concern is the junction outside. I need to make ...
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1answer
2k views

What are the disadvantages of having electrical conduit penetrate my foundation below-grade?

I'm having an electrician wire a lamppost in the backyard. His initial proposal was to do something like this picture shows: (The diagram is from this article.) The conduit's rise from the ground ...
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4answers
36k views

Do I really have to fasten interior-wall electrical wire to a stud to keep it from moving?

I am fresh out of cable staples and would rather not go all the way to Lowe's just to get a box. What are the implications of not fastening loose electrical wires to a stud? It's not like there's ...
12
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4answers
1k 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 ...
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7answers
1k views

What's the least intrusive way to find out what's in a wall?

I'm getting ready to mount a flatscreen TV on our living room wall and would like to route various cables through it (e.g. surround sound speakers, HDMI, etc). I appreciate the AWESOME tips here, but ...
12
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3answers
1k views

What is “knob and tube wiring”?

I assume this is some USA wiring system, am I right?
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7answers
37k 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 ...
12
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3answers
29k views

What's the minimum depth that an electrical box can recess into a finished wall? Does it have to be flush?

Do electrical boxes have to be flush to the finished surface? Can they recess any depth into the wall by as much as 1/8" or 1/4"? Edit: I appreciate everyone offering alternative solutions to ...
12
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5answers
14k views

Why do my new dimmable CFL bulbs hum?

I just spent $100 upgrading our dining room lighting from regular incandescent bulbs with a dimmer switch to a CFL friendly dimmer switch with specifically marked dimming capable CFL bulbs. At full ...
12
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7answers
82k views

Why Do 240V Circuits Not Require Neutral?

Someone told me that a 240V circuit does not require a neutral wire in the cable. Can anyone explain this phenomenon from the electricity perspective and generally explain why circuits do and do not ...
12
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2answers
2k views

Can I use old abandoned iron pipe as electrical conduit?

I have an older house (1920) and I have been planning on doing some rewiring to get rid of some k + t stuff. Anyway, I just noticed today that there are some irons pipes that used to be part of the ...
12
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4answers
57k views

What is the proper way to run wires along/across basement ceiling joists?

I want to add an electrical outlet in my unfinished basement. It makes sense to run the wire along the ceiling because that's where all the other wires are. What is the proper way to install NM ...
12
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1answer
466 views

How to make this electrical main safe

An older home has a strung electrical main. The main connects with exposed lugs on the roof above the deck. Not only is the height and location unsafe, while working on the roof today I noticed that ...
12
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1answer
6k views

How do I know if my wiring is aluminium or copper?

In this answer, Chris has mentioned that, before replacing a worn-out electric outlet, it is important to know whether the building has an aluminium or copper wiring. How can I get this information? ...
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2answers
6k views

Can I change a 1-gang electrical box to a 2-gang electrical box?

I live in a house built in the 50's in Maryland, US. Each bedroom contains 4 electrical outlets - configured in two 1-gang electrical boxes on opposing walls. However, with all the modern appliances,...
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5answers
17k views

Is “don't mix data and power cables” and “don't loop power cables” still valid nowadays?

There are two sayings I keep hearing when talking about wiring e.g. home cinema or computer hardware; Don't wrap data/network cables and power cables up in the same loop because the power cables ...
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7answers
11k views

Can I plug a generator into a dryer outlet [duplicate]

I have an electric dryer with a 30 amp circuit running to it. If I had a male-male plug to run from a portable generator to this outlet, would it be safe to run essential appliances (water pump, ...
11
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2answers
25k 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 ...
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15answers
67k views

When wiring outlets should I use pigtails or both sets of outlet screws?

I'm replacing the outlets in our house and pulled out one that had two black and two white cables. My first thought was that it was two circuits, one of them being switched, but then realized the tab ...
11
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3answers
23k views

What is electrical code for number of wires in a breaker?

US, Georgia I am adding some new ciruits to add some additional outlets. The closest place is to run a wire to the main panel box. My question is, can I connect more than one wire to a breaker and ...
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5answers
11k views

How can I detect reverse polarity on an ungrounded receptacle?

Recently moved into a 1950s-built house and am swapping out some of the older receptacles. On one particular ungrounded circuit there are four receptacles. The first two are as expected - the two ...
11
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3answers
4k views

Is this electrical junction up to code?

I was up in my attic a few days ago, and I noticed a pretty ugly electrical junction that wasn't in a junction box. Here's the pic: Is this up to code? FWIW I live in north Alabama, outside city ...
11
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1answer
14k views

How exactly does a 3-way switch work?

I just finished replacing all of the switches and outlets in my apartment, after fighting a long war with a weird 3-way switch. Needless to say, I won, but I'm still trying to grasp the concept of how ...
11
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4answers
2k views

How do I use three-prong appliances when my outlets are mostly two-prong?

I am living in a house where most electrical outlets are two prong. There are a smattering of three prong, in particular where an addition was put on. Am I hosed when it comes to where I can plug in ...
11
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7answers
50k views

Should I put a dimmer switch on a ceiling fan?

I have a ceiling fan on our bedroom's vaulted ceiling. Since we don't want 7' pull-cords, the speed is stuck at full-tilt, which is no good. The fan has separate switches on the wall for lights and ...
11
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2answers
742 views

How many power cables can a coaxial cable cross?

I am running coax RG6Q to my FiOS box. I know to cross electrical cables perpendicular, but is there a limit to how many wires I can cross in a short area? See my picture: the coax is the black line ...
11
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1answer
8k views

Is it “normal” for a vacuum cleaner to trigger an arc fault breaker?

We recently had our main electric service panel upgraded (from a 50 year old 100 AMP panel to a 200 AMP panel). As part of the upgrade, the electrician installed an arc fault breaker on the bedroom ...
11
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1answer
4k views

How to replace a standard 2-gang light switch with an electric dimmer switch

I'm looking for a some assistance in fitting a new electric dimmer light switch. I'm in the UK if that makes a difference. I am trying to replace my existing two-gang light switch with a LightWaveRF ...
11
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3answers
3k views

What size extension cord should I use for multiple computers?

We're hosting a LAN party (several computers, 50+) and I had some questions about power draw; I hope this is the right place to ask. Currently, we're assuming each PC will draw an average of 3.5 amps....
10
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22answers
1k views

What are some of your previous owner nightmares you have inherited?

Things like picket fences that are screwed and to end and to trees with no posts. Or where there are posts they are sunk 4 inches into the ground with concrete around the top. Or plumbing done with ...
10
votes
8answers
17k views

Is there any legitimate reason you would NOT connect the ground wire on a circuit?

I've been doing some remodeling on my house and had the need to move some electrical outlets. While doing so, I noticed that the ground wire wasn't hooked up on any of the outlets in the circuit (...
10
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8answers
25k views

Does a homeowner need a permit for electrical work in Massachusetts?

Does a homeowner need to obtain a permit from the town in order to do electrical work on his own house in Massachusetts? The unofficial answers I can find online (e.g., this forum and the websites of ...
10
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5answers
31k views

What types of electrical outlets are found in a typical home in the USA?

I do not live in the USA. If I were to buy a home in the USA, what are the key facts I should know about USA household electrical supply at outlets in homes? E.g. when buying a clothes dryer or other ...
10
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3answers
4k views

What are the differences between these two receptacles?

Residential duplex outlets come in a variety of styles. The two most common seem to be: and Does it matter? Is the difference purely aesthetics, or is there any technical difference?
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4answers
3k views

Would running a new subpanel in parallel meet NEC requirements? If not, what should I do?

Background U.S.A. Voltages/power present. My house has a 125A Power Mains breaker at the street. A buried line runs from the street breaker to my main panel on exterior wall outside of house. The ...
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8answers
63k views

How can I run Cat5e cable through a completely finished house?

My family and I are interested in buying a house that was built in 2002. This house is two floors on a concrete slab with a finished bonus room upstairs so there is no attic other than above the ...
10
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1answer
2k views

During a lightning storm, what causes the lights to temporary cut off and on?

I know it is pretty common during a lightning storm for lights to temporary cut off and on, but where and how and why is this occurring? Is the transformer temporally shutting off power to prevent ...
10
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6answers
89k views

How do I add more circuit breakers once the breaker box is full?

My house was completely rewired by the previous owner. They tore out all the old knob-and-tube and replaced it with modern wiring. I definitely appreciate this, but unfortunately they left ...
10
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3answers
11k views

Can I use two wire nuts instead of one to connect 6 wires inside a 3-gang box?

Is it considered acceptable practice to use two wirenuts in a situation where it is possible to use only one but may be easier to use two? I have a three-gang box with six cables coming into it. The ...