Outlets wired backwards

[kenstrac]

What size breaker do you have on the #10 if its 30 you can not use that outlet if it's 20 you must have a 20 amp receptacle not a 15.
Wapedia - Wiki: NEMA connector

BTW never hooked a GFI backwards will it work or will it trip?

 

[Egon]

??? Then the light would never go out, but that couldn't happen,

You got hot to light and the return is hot to the switch. The switch interrupts the return.

 

[MossRoad]

The only time I encountered low voltage was in Elkhart, IN,

How appropriate that Elkhart is the RV capitol of the world!

 

[MikePA]

I think it was a good point, Mike... If the plugs are wired in reverse polarity AND the ground is removed all it would take to ZAP the bajeebers out of you is if you touched the case of a cheap appliance and a metal window frame on an aluminum sided house. Weird stuff like that happens.

Now that you've explained the connection to reversing the polarity and grounding, I agree. It was clear as mud before. However, I think Egon has nailed the direct issue to the OPs question, i.e., flipping a switch will not interrupt the hot wire if the polarity is reversed which could get worse, if there's a bad ground. All in all, correcting it is the right thing to do.

 

[ray66v]

Hopefully the house is wired properly, and the mistake was made by the person who did the finish work.

Another cause for concern is if every part has price tag on it.

In the 80's switches, and receptacles with push in terminals were common. If you have those, put the wires under the screws. Do not use the push in connections.

I would find someone who is qualified to have a look at the job, to be sure if it was all done properly. It usually takes about 10 seconds looking at the inside of the service panel, to tell if the person who wired it knew what they were doing. Things like an overloaded neutral wire, improper connections, and undersized wire, can be a serious issues.

 

[bbirder]

Hey guys,
This can be a serious problem and I want to say that you should not assume your wiring is correct just because a licensed electrician did the job. I had an old house rewired two years ago by a licensed electrician, because I didn't have the time to do it myself. After he finished, and was paid I might add, I went behind him and found that all the receptacles in the house had the ground wire disconnected. His hired help was not licensed and did a poor job. Not a grounded outlet in the house, and my grandchildren were moving in. I can assure you he got a piece of my mind, and he personally came back and did the job over.

 

[jinman]

I used to own a house where some "handy" previous owners did their own home remodeling and removed plugs while doing it. The whole house was 2-wire construction built in 1950. When power came to the circuit breaker box, the earth ground was attached to the same bus as the neutral. The handy owners decided to replace the receptacles with three-prong plugs and just connected the third prong to neutral. Unfortunately, they also reversed the hot and neutral wires on one wall, making the chassis ground to anything connected at the full hot potential. There were no ground fault connectors in this whole house.

I guess this condition must have continued for many years and then I discovered personal computers. This room just happened to be my office. I bought a new computer and printer to sit on my desk. I hooked the computer and monitor into one wall receptacle, but didn't have a power strip, so I hooked the printer into the other wall receptacle and started to run the printer cable to the computer. POW! As soon as the printer cable's shielded jacket touched the computer's plug, there was a big flash and the CB popped in the box. To this day, I don't know how I avoided being electocuted. I remember how my heart raced when the sparks flew and how I was certain my new and expensive computer was toast.

I pulled the cover on the wall receptacles and immediately saw the problem. I fixed the miswire in both receptacles and checked every other one in the room. Luckily I was smart enough to not reset the breakers until I checked out what was wrong. I was even more lucky in that both the computer and the printer worked perfectly when I again powered them up. WHEW!

 

[Heywood Jannockitov]

I ran multi-strand awg 10 in schedule 40 conduit in my barn to a new addition that was at the opposite end from where the load center is located. Why did I use 10 gauge? It was free. I had 2, 300 metre spools given to me, one white, one black. That's about $600 on copper wire I didn't have to spend.

I added 6-15 amp and one 20 amp circuit which were minimum 80 feet runs to the first junction. I simply pig-tailed all connections to switches, receptacles, fixtures with awg 12. It's no problem to fit the 10 gauge wire into a 15 amp breaker. Just had to buy colored electrical tape

Took a long time to wrap green or red electrical tape around 150 metres of wire. (sorry, just kidding!)

 

[MossRoad]

All in all, correcting it is the right thing to do.

Yeah. That's the right thing to do. I'd better do it, too. We've been in our house for 13 years and there are still some electrical problems left over from the last owner. Nothing major, but it should be corrected.

 

[tallyho8]

What are the consequences, dangers, problems that result from using outlets with neutral and hot reversed? Jack

Jack

Back to your original question, what are the dangers? I was a refrigeration, air conditioning, appliance technician for 38 years and found many dangers with such an arrangement.

Many times when a motor or heater burns up, it shorts out to ground. In many older homes that originally had 2 hole 110v outlets without a ground, the outlet went bad over the years and were replaced with a 3 hole outlet without a ground wire connected.

When the motor shorts to ground on a grounded outlet it will blow the fuse but if the outlet is not grounded it sends 110 volts to the chassis of the unit. Many times I opened the door of a refrigerator before the customer answered my question, "What problem are you having with the refrigerator?" I always knew the answer before they said "it shocks when you touch it".

One of the main dangers in having a switch wired backwards is that the hot wire will not turn off when you turn the switch off. It just turns off the neutral. When I change a light fixture I never turn off the circuit breakers, I just turn off the switch. Doing this while standing on an aluminum ladder with reversed wiring can result in severe injury or death.

I do not envy your difficult job that lies ahead but you must correct the situation ASAP. I recommend that you also install GFIs in the first outlet in each circuit for further protection as you remove and repair them.