I want to replace some power outlets in my condo with ones that have built-in USB ports. The condo was built in 2008.

My thinking is I can simply turn off the breaker for those outlets and get to work. But then I thought... what if those outlets are mis-wired? Should I use an outlet tester?

What is the best way to be safe when replacing power outlets?

  • 7
    In my view, ALWAYS check the outlet after switching off the circuit to make sure it's OFF. Don't bet your life on having found the right breaker!
    – jwh20
    Dec 21, 2019 at 21:59
  • 1
    Does this answer your question? Electric shock - was I stupid, unlucky, or a combination of both?
    – Mazura
    Dec 21, 2019 at 22:13
  • The best way to be safe is to have someone who knows how to do it, do it. And the best way to answer an electrical question is to not respond in-kind with what is presumed to be the OP's level of understanding.
    – Mazura
    Dec 21, 2019 at 22:17
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    Those that vote to close are ignorant of the DIY goal of this site! In every place I have lived after becoming a journeyman electrician in the 70’s allow a home owner to do there own repairs , a replacement of a receptacle, switch and fixture is legal in every place I have lived and worked. The question is simple direct and other than specific devices used is 1000% what this site is about, those that down vote without a comment should have a -100 as that is a coward way in my opinion this is the reason we are here!
    – Ed Beal
    Dec 22, 2019 at 2:05
  • 1
    Where do you live? Looks like US and UK are special when it comes to wiring.
    – Michael
    Dec 22, 2019 at 16:56

3 Answers 3


We have a FAQ for novices doing receptacles.

There are many tricks and traps when changing receptacles. I wrote a Q&A specifically for folks like you, please review it.

The #1 thing I'd say that isn't mentioned there is don't downgrade an outlet from GFCI to USB (unless it's redundant).

Speaking of testing, those 3-lamp testers have 3 Rather Useful lights which let you do three tests at once. (Obviously, if any lights light, the outlet is most likely hot; but that is not enough.) But the little chart/legend is completely wrong; it's about as useful as a "magic 8-ball". It's actually optimized for new construction; once built, houses have different kinds of problems.

  • However, the GFCI tester function is very nice; if you suspect a redundant GFCI, use the 3-lamp tester's TEST button. It will trip this GFCI (obviously). But if this one turns stone dead and refuses to reset, it tripped another GFCI somewhere else, which means this one is redundant and doesn't need to be a GFCI.

As far as safety, once you're opening things up, turn the entire house off and check it by plugging a lamp into both outlets. There are so many surprises and gotchas for the novice (MWBC, borrowed neutrals, you name it) that it's not worth fooling around any other way. It's what I do myself in our factory building; I pull the main 480V which shuts off all the 120/240V transformers.

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  • The op said nothing about changing from GFCI to “usb” so this is silly. A building wired in 08 to code would have 3 wire and the wire color codes are defined in code as they have been for many decades.
    – Ed Beal
    Dec 22, 2019 at 1:55
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    @EdBeal OP didn't say not, either. You dv'd for mentioning not to replace a GFCI with USB? Seriously?. And your whole justification is that a house built in '08 will be to Code? Seriously?. Because what, 2008 houses never use GFCI recps? Or because people will never want USB receps in a kitchen or bathroom? Dec 22, 2019 at 2:17
  • This is where you and I disagree, A condo is a commercial building by code in my location and has 2-3x the required inspections of single occupancy residency, since the usb receptacles were approved I have installed in every kitchen our company has built !
    – Ed Beal
    Dec 22, 2019 at 2:25
  • 2
    @EdBeal Right, but what about the other people who will read this post and look for advice? Dec 22, 2019 at 2:56
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    @EdBeal I'm with Harper on this one. There are convenience reasons to have GFCI in bathroom or kitchen be at the receptacle rather than the breaker, so the warning is very important. OP might not realize that it is a code requirement and end up with a dangerous situation. Dec 22, 2019 at 3:16

An outlet tester is a great way to determine that an outlet is wired correctly. They are also useful to show that the correct breaker has been tripped before you start working. Take pictures before you disconnect anything so you'll have accurate information in case you have to come back here and ask questions. Follow the directions that will be included with the outlets. Also, make sure none of the outlets are switched as that could interrupt your charging.

  • Using an outlet tester to verify the circuit is dead is a good idea I always use a meter or tic tester (no contact for a quick test) rub it on my shirt it beeps test it should not beep then rub on my shirt again by testing it before and after this method passed local osha inspection.+
    – Ed Beal
    Dec 21, 2019 at 21:40
  • 1
    Outlet testers (magic 8-ball) testers are optimized for new work. In old work, they give very misleading answers, hence my name for them :) Dec 21, 2019 at 21:45
  • I agree with the magic 8 ball name but have never had a false reading if they said the circuit is hot it is , tic testers may be triggered by phantom voltages.
    – Ed Beal
    Dec 22, 2019 at 1:51

You are correct in thinking to turn the breaker off.

Since your place was built in 08 it will be wired to code. The new receptacles will usually have 3 different colored screws. Brass color is hot normally the black wire Silver color is neutral normally the white wire And last a green screw the equipment grounding is normally a bare copper Since you are in a condo the colors may be slightly different the hot Brass screw could connect to any color other than white, gray or green. The neutral silver screw may be white or gray only. And the equipment grounding green screw will be green or bare copper.

Your outlet may say hot , neut next to the screws i don’t remember seeing any UL approved receptacles that don’t have the colored screws.

Last don’t use the back stabs wrap the wire 2/3 to 3/4 wrap around the screw and torque to the MFG specifications. (Back stabs have a high failure rate).

  • 1
    All the ones I've installed didn't have backstabs but had the back clamp connections with one or two holes per terminal. +
    – JACK
    Dec 21, 2019 at 21:32
  • 2
    I also prefer “back & side” receptacles they cost a little more but are built to higher specifications than the cheap home owner grade +
    – Ed Beal
    Dec 21, 2019 at 21:36
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    "it will be wired to code" - you misspelled should. And failed to list and explain how to use all the safety equipment needed to do electric work.
    – Mazura
    Dec 21, 2019 at 22:12
  • osha has no leverage on a home owner! So you are wrong but as a professional and a lead electrician, I have not Been cited or fined as my employers have been protected by my policies based on both the osha requirements and the NEC are not violated , even inspected installations that have passed inspections and later have failed because they were not to code SHOULD have been wired to code that is why I explained the proper color code and wire wrap required by code.
    – Ed Beal
    Dec 22, 2019 at 1:47

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