NEMA 14-50 8 gauge wire

[ucmndd]

Why? A 120V device is the only thing looking for a neutral. If the neutral leg isn't there, the device simply wouldn't get power.

Most RVs use 14-50s as two 120v circuits.

Most electric ranges use 240v for heating elements and 120v for control electronics.

 

[CKwik240]

Most appliances use a 14-50 because they need both 120v and 240v. Unfortunately, leaving the neutral out does not necessarily mean the 120v parts simply get no power. Instead the return voltage can find it's way through other parts of the circuit to the other leg or to ground.

It's even worse in the case of something like an RV which will have appliances connected to both 120v legs. The return voltage will find it's way through the wiring to another appliance and through it to the other leg. Since the neutral is floating one appliance may see a low voltage and the other may see a very high one. Finally, you can end up with a hot chassis if one of those appliances only has a two prong plug, creating a shock hazard.

Thanks for this response. I did think of that to a small degree and I would agree a single appliance using 120 and 240V could cause such an issue. This may include if such a device were connected in the home/RV. But I can't think of how this would happen unless something were wrong with such a device. I've seen some interesting ground path issues with 12V DC systems, but these exists because the chassis is used as part of the ground. I'm not aware of any appliances that are designed to pass neutral through the device chassis. But I would concede that having the neutral would be important for the just in case scenario. Unless you know of a scenario where this happens inherently.

 

[Rocky_H]

Why? A 120V device is the only thing looking for a neutral. If the neutral leg isn't there, the device simply wouldn't get power.

I thought that too until I learned how this actually works and watched some Youtube videos explaining it. Here's what actually happens like in an RV.

It is using the connection as if it's two circuits of 120V. Inside the RV's electrical panel, there is a shared neutral, but it's expecting that to be tied down to 0V to hold it in the middle. If it's not, then it's really nothing more than a pass-through wire joining the two circuits together.

I'm going to refer to "A side" and "B side" as like the two sets of 120V circuits that have the common neutral that is disconnected. You have several things like lights, power outlets and such on each of those sides. What you end up having is A side and B side connected across a total of 240V with nothing to force it to stay evenly with 120V on each side. So with random combinations of things plugged in, the resistance will be uneven, and the voltage may shift wildly, like 40V on one side and 200V on the other. Some appliances built only to accept 120V may pop or blow their power supply and start a fire if they get 200V on them that they are not prepared for.

If you search Youtube for "missing neutral", you can find some good videos on it with demonstrations.

 

[CKwik240]

I thought that too until I learned how this actually works and watched some Youtube videos explaining it. Here's what actually happens like in an RV.

It is using the connection as if it's two circuits of 120V. Inside the RV's electrical panel, there is a shared neutral, but it's expecting that to be tied down to 0V to hold it in the middle. If it's not, then it's really nothing more than a pass-through wire joining the two circuits together.

I'm going to refer to "A side" and "B side" as like the two sets of 120V circuits that have the common neutral that is disconnected. You have several things like lights, power outlets and such on each of those sides. What you end up having is A side and B side connected across a total of 240V with nothing to force it to stay evenly with 120V on each side. So with random combinations of things plugged in, the resistance will be uneven, and the voltage may shift wildly, like 40V on one side and 200V on the other. Some appliances built only to accept 120V may pop or blow their power supply and start a fire if they get 200V on them that they are not prepared for.

If you search Youtube for "missing neutral", you can find some good videos on it with demonstrations.

Turns out, this is one of those things that is better to draw out. I was picturing the circuits in my head and kept imagining the missing neutral at the plug of each device. With the neutral disconnected at the source, it leaves a path between the 240V legs through the neutral on devices that are turned on. Got it. Thanks.

 

[Rpgonzalez]

Most appliances use a 14-50 because they need both 120v and 240v. Unfortunately, leaving the neutral out does not necessarily mean the 120v parts simply get no power. Instead the return voltage can find it's way through other parts of the circuit to the other leg or to ground.

It's even worse in the case of something like an RV which will have appliances connected to both 120v legs. The return voltage will find it's way through the wiring to another appliance and through it to the other leg. Since the neutral is floating one appliance may see a low voltage and the other may see a very high one. Finally, you can end up with a hot chassis if one of those appliances only has a two prong plug, creating a shock hazard.

So I did that with a buddies RV. I have no idea why I had a 6-50 to 14-50 adapter laying around, but in my ignorance decided to just use it. The RVs inverter literally burst into flames. I still have no idea why the inverter blew, but it happened!