All Questions
5,056
questions
38
votes
2
answers
25k
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?
...
112
votes
7
answers
658k
views
How can I add a "C" wire to my thermostat?
So, the spiffy new wi-fi thermostats want power on the C wire from thermostat, but the old thermostat doesn't have a C wire at it. What's the easiest way to add the C wire/24 volt to the thermostat ...
- 6,381
20
votes
3
answers
2k
views
First time changing switches and outlets (receptacles). Anything special I should know?
I am replacing a bunch of switches and receptacles in my house.
While I understand the basics, this is pretty much my first electrical project, and I figure there must be some hidden "gotchas" or ...
28
votes
3
answers
938k
views
What wire gauge do I need for a 100 Amp subpanel at the end of a 60' wire run?
I am adding an attached garage to my house. I'm going to be putting in a 100 Amp subpanel which is about 60 feet away and run through the basement joists.
What gauge wire do you recommend for ...
- 281
36
votes
3
answers
29k
views
When doing electrical work, what do I use to check wires are safe?
If I am thinking of replacing a light switch, a light-fitting, a socket/outlet or doing other work with household wiring where there may be 120 Volts or 240 volts present ...
There is already a ...
- 24.1k
31
votes
6
answers
8k
views
Electric shock - was I stupid, unlucky, or a combination of both?
One of the double sockets in our garage needed replacing (damaged after a washing pole hit it) - a pretty trivial job that I'd done before. So I flipped the MCB for the ring main, used a non-contact ...
- 311
46
votes
4
answers
43k
views
Are there ways to determine if a wall is load bearing?
Other than looking up blue prints, which many homeowners may not have, are there ways to determine if a wall is load bearing?
Methods I can think of might include:
Going up in the attic to check if ...
- 15.6k
29
votes
9
answers
302k
views
How do I install a GFCI receptacle with two hot wires and common neutral?
In my kitchen, I want to replace a regular 120V receptacle with a GFCI-protected receptacle. The instructions describe what to do with a regular 2-wire + ground feed, with and without daisy chaining ...
- 475
48
votes
10
answers
69k
views
Should old knob and tube wiring be replaced?
I have been doing some electrical work in my house and I noticed it has old knob and tube wiring that is still hot, should this be replaced as found or is it fine to just leave it? It seems really ...
- 131k
32
votes
5
answers
57k
views
Is it OK to borrow a ground wire from a different circuit?
I've got a circuit in the basement carrying a handful of outlets. This circuit has no ground wire. I want to add a couple of outlets and want them to be grounded. I may even want gfci outlets on ...
- 2,350
24
votes
6
answers
24k
views
What benefit do plasterboard/drywall screws have?
I have some plasterboard screws like this:
However, without a drill I have a job getting them into the wall. Am I safe to use normal screws on hangings that aren't going to be taking a great deal of ...
- 343
42
votes
1
answer
201k
views
What are the guidelines for holes in joists?
I've been unable to find a good reference for the size/amount/location of holes I can drill through joists. This is mostly in order to pass cabling or pipes through the joist crosswise. Also, what ...
- 6,381
31
votes
5
answers
477k
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 ...
- 5,085
31
votes
4
answers
151k
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 ...
- 716
40
votes
9
answers
123k
views
Should I use steel or wood studs for basement exterior walls?
Related: When should you use metal studs?
I'm planning on finishing my basement. (assuming all water issues are resolved)
I'll be putting up a water barrier (tar paper) on all exterior walls, ...
- 14.1k
29
votes
9
answers
137k
views
Is there a way to simply splice in an additional length of 12/2 NM-B cable?
Is there a way without using junction boxes to simply splice in additional length of 12/2 NM-B cable? Can I use twist caps?
I'm putting in a dog door and as it so happens, there is some 12/2 right in ...
- 557
43
votes
12
answers
304k
views
Is using 15 amp components on a 20 amp breaker against code?
I have noticed in a few different houses in Oklahoma that 20 amp breakers are used, but all of the outlets and switches only seem to be rated for 15 amps. This goes against everything I know to be ...
- 2,040
41
votes
3
answers
484k
views
Why do my LED lights stay on, even when the switch is off?
I have two LED lamps in my corridor, and when I switch them off, they keep emitting light (not very strong, but it's annoying at night).
What can it be? How can I fix it?
- 539
62
votes
7
answers
467k
views
Can Romex (NM-B) cable be run through conduit?
A few days ago I asked an electrician if I could run cable through conduit - he gave me a funny look and said "No, Romex is not allowed in conduit."
When I searched online, there seems to be ...
4
votes
2
answers
106k
views
Unexpected voltage with switch turned off
I am doing some work on a ceiling light and I notice that, even though the light-switch is off, my voltage tester shows voltage present.
Answers to other questions (below) explain about phantom ...
- 24.1k
31
votes
8
answers
153k
views
How do I rehang a wooden door with worn screw holes?
I have a wood door in one of my rooms where the top screws no longer hold the hinge to the wall because the screw holes have worn loose. I have tried slightly larger screws and filling with wood ...
user2278
14
votes
4
answers
6k
views
Why not use a plastic receptacle box for an outdoor outlet?
This answer says "... it should be possible to cut into the wall and install a metal box (don't use plastic, please) [for an outdoor outlet]."
What are the problems associated with using a ...
- 1,045
13
votes
4
answers
311k
views
Where does the ground wire go in a 3-prong dryer cord configuration?
We moved to a new place where the dryer connection is 3-prong instead of 4-prong. The dryer was originally 4-prong, so we bought a 3-prong cord and installed it. It works fine, except I am not ...
- 233
12
votes
2
answers
116k
views
How do I identify the C terminal on my HVAC?
How do I identify the C terminal on an HVAC, furnace, or boiler? If the terminals don't have a screw labeled C what should I look for on the wiring diagram? What steps should I take if a wiring ...
- 42.6k
2
votes
5
answers
5k
views
What to do with a new duplex outlet when the tester says Hot & Ground are Reversed?
I switched out a regular outlet with a LeGrand Radiant Duplex Outlet, connecting all of the wires (2 White, 2 Black and 1 Green) exactly as the previous outlet was wired and according to the ...
- 21
42
votes
8
answers
510k
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 ...
- 7,293
41
votes
10
answers
286k
views
Can I run CAT5/6 cables parallel to electrical cables?
I am building a new house and am planning to hardwire network cables into each room.
Can I run CAT5/6 cables parallel to electrical wires without introducing any general safety issues or losing much ...
- 513
13
votes
2
answers
69k
views
Why am I measuring 16 volts on a wire that should be at 0 volts?
I am replacing a power receptacle at my apartment. It has the standard four wires, with one of the two reds going to a nearby toggle switch.
I am concerned because when the toggle switch is off, I ...
- 481
11
votes
8
answers
183k
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 ...
- 227
4
votes
4
answers
50k
views
Is it OK to use 1/4" concrete backer board over 1/2" plywood as a bathroom subfloor?
I just bought a house built in 1978 and I'm planning on putting tile in the bathrooms (currently linoleum).
The fixtures are removed and the flooring under the linoleum is particle board. I think ...
- 1,069
85
votes
13
answers
93k
views
How to remove screws with stripped heads?
I have wood screws whose heads are stripped from trying to remove them with a drill. The drill (or screwdrivers) can't grip the heads anymore. What can i use to remove these screws easily?
- 1,005
36
votes
8
answers
10k
views
How best can I discover what is up with my electrical bill?
This might be subjective, I don't know. However, it's a serious problem for me. My electrical bill is outrageous. It's three times as large as my next-door neighbor, and four or five times the size of ...
- 503
18
votes
10
answers
271k
views
Why would a GFCI trip on refrigerator circuit?
My refrigerator is tripping the GFCI on the socket into which it is plugged. Searching about this topic seems to indicate that this is a reasonably common complaint. However, I can't find any ...
- 283
24
votes
6
answers
237k
views
What is the proper 'per code' method for running nonmetallic sheathed cable above a ceiling in the attic?
Can the wiring be run over the top of the ceiling joist, or must it be run through bored holes when running perpendicular to the joists?
This is a non-habitable space, will have an attic entrance ...
- 241
20
votes
4
answers
224k
views
Should the backer board be in front of or behind the tub flange?
I'm installing a new bath tub and shower. I've removed the old tile down to the studs.
Should the backer board be in front of or behind the tub flange? I put it on the rear tub wall from floor to ...
- 201
13
votes
2
answers
17k
views
How can I replace 2-prong receptacles in a code compliant way?
I have some 2-prong non-grounding type receptacles, and I'd like to replace them with 3-prong grounding type receptacles. According to National Electrical Code, what are my options?
- 131k
12
votes
5
answers
83k
views
Can different gauges of wire be used on the same circuit?
My father-in-law is a builder. He has put in 20 amp and 15 amp breakers, and ran 12-2 as the home runs to the switches and the first plug to make them hot. He then ran 14-2 to feed the rest of the ...
- 131
139
votes
11
answers
111k
views
How to prevent heavy rainwater from jumping the gutter?
During heavy rain, the water collects from my second floor roof and runs onto the first floor roof as it should. The problem is that since all this water is now concentrated from the second floor ...
- 1,373
40
votes
4
answers
323k
views
How should I rewire a miswired 3-way switch?
I have a 3 way switch that was wired incorrectly when the switches were replaced with a different color switch. Is there a methodical way for me to identify which wires represent which piece of the ...
- 661
33
votes
6
answers
408k
views
When should pipe dope vs thread tape be used?
For threaded plumbing connections, you typically use pipe dope or thread tape (aka teflon tape). Are there situations when one is preferred over another? Does the size of the pipe, type of pipe, part ...
- 42.6k
28
votes
6
answers
140k
views
Where should I NOT use a GFCI or AFCI?
There is a lot of information out there about the benefits of GFCI and AFCI and the places where they must or should be used. But are there any circumstances where you're better off without them? If I ...
- 617
27
votes
3
answers
7k
views
Now I realize I used too many GFCI outlets. How can I reclaim them?
Yeah, so the building inspector redflagged a bunch of outlets for not being GFCI. Before I understood how the LOAD terminals work, I just replaced every single one with a GFCI outlet. Most had a ...
24
votes
7
answers
16k
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 ...
- 249
14
votes
1
answer
7k
views
How do I correctly install ceramic floor tile?
How do I correctly install ceramic floor tile? There's lots of talk about using backerboard and waterproofing membranes, what an acceptable floor deflection is, different grout and thinset additives, ...
- 13.3k
30
votes
7
answers
101k
views
Extension cord and power strip safety
I've heard that there are some safety and building code issues involved with using extension cords or power strips (surge protectors) for anything other than temporary use. What are the issues, and ...
- 821
13
votes
4
answers
174k
views
How to properly ground a subpanel in detached building?
I Will be installing a subpanel in a detached garage. The subpanel will be 60 amp. The garage is about 30' from the main-panel in-house, and I will of course get an exact length before selecting the ...
- 1,074
13
votes
1
answer
187k
views
What size wire should I use to feed a subpanel in my garage?
My main panel has been upgraded to 100 amps. I would like to add a subpanel in the garage which would supply:
20 amp Mig welder running on 120 volts, but later upgrade to a larger Mig welder as i ...
- 131
12
votes
3
answers
9k
views
Can ground shock me? It's bonded to neutral in my panel
I have no outdoor outlets. I want to install a GFCI outlet underneath my main service panel.
Inside the panel there is only one bar with both ground and neutral wires connected to it. If I connect ...
- 121
10
votes
2
answers
77k
views
Is an explicit ground wire required through steel conduit?
We just bought a Chicago-area house and found that there's no ground wire in some of the recently re-wired areas. I thought that the national electrical code requires a ground wire for new ...
- 1,430
8
votes
1
answer
91k
views
How do I wire a GFCI/Switch Combo?
I'm replacing an old GFCI/Switch combo. In the old one there are two wires coming into the line side, a hot wire and a neutral. On the load side there is one wire leading up to the lighting fixture. ...
- 221