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Mattyboy

50 Amp Service Wired Wrong

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Mattyboy,

You need to get a simple Volt/Ohm meter and learn how to use it. Outlets need to be checked in campgrounds before plugging in just to be sure some of these kind of things don't happen again.

By the way, 220 Volt only happens in other countries, it is 240 Volt here.

John

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On 1/25/2015 at 8:16 AM, wolfe10 said:

Since your RV is 50 amp service, I ASSUME that the 4 wires were mis-connected, with one of the two hots going to what is supposed to be the neutral. If the mis-connected hot was to ground, the RV skin/frame would have showed 120 VAC and a good chance someone would have been electrocuted.

If that was the case (mis-connected to neutral), only those circuits supplied by that one properly wired hot (and the mis-connected one on neutral) should be affected. Said another way with just two hots and one of them mis-connected, the circuits supplied by the hot that was mis-connected would have showed 120 VAC (but with reverse polarity) if the mis-connected was on the neutral. They should have suffered no damage.

Just found this issue at a brand new park today and have a question about this......

Here are my readings off the 50 amp plug:

We're going to name the plug holes like a compass.... North, South, East and West.

Readings:   West to South = 240V,   West to East = 120V, West to South = 120 V.        (I know I should have read, in order, 120V, 240V, 120V)

My guess is the bottom (south) leg which is "neutral"?????  is hot with 120V, which gives my line 1 hot, and "neutral" the 240V reading.... the hot neutral with line 2 giving me 120V is telling me that they connected ground to what should be line 2 hot..... correct?    

So, if I had been dumb enough to plug in, I'd have had 120V going through the skin of my coach?   Or would that only be if the 120 was connected to the top (north) hole of the 50 amp plug?

 

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Looking at the 240 volt 50 amp plug, and naming it like you have, East West, that is L1 and L2, measurement across these two should read 240 if this is wired correctly. Now assuming that the plug is not upside down, the south position (straight blade) should be neutral, and you should read east to south 120 volts, and west to south should read 120 volts. The north position should be the only round connector and this one is frame ground, it will also read 120 east to north and 120 west to north if wired correctly. Neutral, south to north (frame ground) when testing your cord with an ohm meter should read open, if this is not correct, then there is a miswiring within your coach, but reading on the CG pedestal should read 0, or dead short, this is correct, and if it reads open then the CG pedestal is not wired correctly. Good luck, and according to your statement about CG pedestal, it is incorrectly wired. Glad you didn't plug in your coach, not only the skin of your coach would have been live, but everything electrical would probably have been toast.

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The good news is that an RV 50 amp outlet is EASY to identify:

 

Two straights (E-W) are hots

Center straight is neutral

Center round is ground

SO,  E to W= 240 VAC

E or W to either center straight or round= 120 VAC

Center straight to center round= 0 VAC

 

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Eric, do you have a portable EMS? I also carry this gadget 

https://50amppowerpal.com

A wise man once shared this link and I ordered one immediately. 
Portable EMS would have alerted immediately also. 
here is the diagram I keep in my phone just in case.

CC580681-B556-4B51-9D2F-DD148CDD6590.jpeg

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18 hours ago, kaypsmith said:

Looking at the 240 volt 50 amp plug, and naming it like you have, East West, that is L1 and L2, measurement across these two should read 240 if this is wired correctly. Now assuming that the plug is not upside down, the south position (straight blade) should be neutral, and you should read east to south 120 volts, and west to south should read 120 volts. The north position should be the only round connector and this one is frame ground, it will also read 120 east to north and 120 west to north if wired correctly. Neutral, south to north (frame ground) when testing your cord with an ohm meter should read open, if this is not correct, then there is a miswiring within your coach, but reading on the CG pedestal should read 0, or dead short, this is correct, and if it reads open then the CG pedestal is not wired correctly. Good luck, and according to your statement about CG pedestal, it is incorrectly wired. Glad you didn't plug in your coach, not only the skin of your coach would have been live, but everything electrical would probably have been toast.

North and south as you stated  I assume you mean  Neutral and ground  they are attached to the same metal box so are connected so Ohm meter will not show  open 

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3 minutes ago, bm02tj said:

North and south as you stated  I assume you mean  Neutral and ground  they are attached to the same metal box so are connected so Ohm meter will not show  open 

Slight clarification.

Neutral and ground are NOT connected at the CG pedestal.  They ARE connected at the CG main distribution box

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2 hours ago, bm02tj said:

ut they are connected so not open

Neutral and ground should never be connected within the RV, as Brett stated they are supposed to be connected at the CG main distribution panel, this is why I stated that you should see a direct short when testing the CG pedestal, he is correct that they are not connected at the pedestal but that short will show up as shorted on the pedestal. If they are shorted when you check the shore power cord, then there is a miswiring within the coach.

 

9 hours ago, wolfe10 said:

They ARE connected at the CG main distribution box

If both are connected to the same metal box within RV, that is incorrect, everything between the CG main panel are considered to be sub connections, therefore the ground is to be isolated from the neutral, failure to adhere to this condition makes all appliances after the within the circuit to be a potential risk for a shocking experience, including the CG pedestal. Please refer to the link below for more clarificarion.

https://diy.stackexchange.com/questions/149477/when-did-the-nec-code-start-to-require-the-separation-of-neutral-and-ground-bus

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Not in the RV in the service as it comes into the property they are connected to the same panel in different locations inside the first disconnect panel

They are talking about testing the power source not the RV

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I would suspect he has the problem rectified between 2015 and now.

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Rich.

Your quite right.  Most Q & A, that we get today, was covered in another tread 2 - 10 years ago and makes it worthwhile to cover again!

Nobody want's hot skin and be lit up like Christmas from touching your own RV. 

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