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RoadTrip 01-28-2013 10:30 AM

Quick electric question
 
I have a house 50amp receptacle, two pole with two 40amp breakers. Does this sound right?

Licensed electrician installed, but he's been hard to get ahold of. I guess I just didn't expect a two-pole design for 110. Can someone smarter than I tell me if this seems kosher?

I realize I have a 30 amp MH, and realize that we'll only need an adapter to plug in, but when we told the electrician we want an RV plug in - we didn't own an RV so those where his only instructions - and now we're trying to figure out if we have a 220 line or 110 line.
thanks!

Herk7769 01-28-2013 10:38 AM

Well, I think (hope) he installed a 50 amp service fused to 40 amps (well within your needs BTW). Hopefully he used a 3 wire with ground wire (black, red, white, and copper).

You see your house current is 220 volts at the top of the panel but you have a neutral grounded in the box. Each "pole" of your 2 pole breaker is 110 volts (1 pole A phase and the other pole B phase) since each pole is returned via the neutral to ground and you should never see 220 volts at the plug if it is wired correctly and you test the socket to ground or neutral (and not the other hot leg).

The 50 amp service, when wired correctly, is 2 110 volt circuits on different phases so that when one leg is hot the other leg is cold every 1/60th of a second (60 cycle power).

Did that help or confuse?

prairiecamper 01-28-2013 10:42 AM

A 50 amp receptacle with two 40 amp breakers would suggest to me 220 volt! Don't plug anything in until you know for sure!

Herk7769 01-28-2013 10:44 AM

Yes, a properly wired 50->30 adapter will only use one pole of the two available.

No way to tell which without tracing the wires back to the panel. It does not matter since the 220 breaker in your panel (2 110 breakers linked together) will trip if any individual leg is overloaded.

RoadTrip 01-28-2013 10:49 AM

Quote:

Originally Posted by herk7769 (Post 297545)
Well, I think (hope) he installed a 50 amp service fused to 40 amps (well within your needs BTW). Hopefully he used a 3 wire with ground wire (black, red, white, and copper).

You see your house current is 220 volts at the top of the panel but you have a neutral grounded in the box. Each "pole" of your 2 pole breaker is 110 volts (1 pole A phase and the other pole B phase) since each pole is returned via the neutral to ground and you should never see 220 volts at the plug if it is wired correctly and you test the socket to ground or neutral (and not the other hot leg).

The 50 amp service, when wired correctly, is 2 110 volt circuits on different phases so that when one leg is hot the other leg is cold every 1/60th of a second (60 cycle power).

Did that help or confuse?

helpful - very helpful. Do I need to go buy a tester of some sort, or is the fact that the receptacle itself says "50amp" on it enough evidence that it's not 220 (i have no idea if there even can be a 50amp with 220)

Herk7769 01-28-2013 10:52 AM

Quote:

Originally Posted by prairiecamper (Post 297553)
A 50 amp receptacle with two 40 amp breakers would suggest to me 220 volt! Don't plug anything in until you know for sure!

A 50 amp RV socket is actually wired from a 220 breaker; just the neutral needs to be carried to the socket as well as the 2 - 110 hots of the 220 breaker.

A "true" 220 appliance does not need a neutral and is typically wired with 2 hot wires and a copper ground wire (no neutral). Examples of 220 only appliances are a 220 volt water heater or dryer.

Wiring a 30 amp RV socket using a wiring set up like a dryer is the danger. While a 30 amp RV socket LOOKS like a dryer socket and should be 220; it is NOT.
It is wired 110 volts like a duplex wall socket.

Far less likely the electrician got it wrong (through not impossible) with a 50 amp service.

prairiecamper 01-28-2013 11:02 AM

Yes I know, but since you were already there I didn't elaborate! You're faster than a speeding bullet BTW. Thanks

prairiecamper 01-28-2013 11:09 AM

Quote:

Originally Posted by herk7769 (Post 297557)
A 50 amp RV socket is actually wired from a 220 breaker; just the neutral needs to be carried to the socket as well as the 2 - 110 hots of the 220 breaker.

A "true" 220 appliance does not need a neutral and is typically wired with 2 hot wires and a copper ground wire (no neutral). Examples of 220 only appliances are a 220 volt water heater or dryer.

Wiring a 30 amp RV socket using a wiring set up like a dryer is the danger. While a 30 amp RV socket LOOKS like a dryer socket and should be 220; it is NOT.
It is wired 110 volts like a duplex wall socket.

Far less likely the electrician got it wrong (through not impossible) with a 50 amp service.

Our dryer plug has a neutral as I believe the motor is only 110 and requires the neutral.;)

RoadTrip 01-28-2013 11:10 AM

whew - thanks herk! I wouldn't think there'd be any confusion b/c not only did we tell him its for the RV, he labeled it as such AND it's in the garage - in the RV bay.

while I'm typing this out - just heard back from the electrician. 220!

TURBS 01-28-2013 11:14 AM

Quote:

Originally Posted by RoadTrip (Post 297567)
whew - thanks herk! I wouldn't think there'd be any confusion b/c not only did we tell him its for the RV, he labeled it as such AND it's in the garage - in the RV bay.

while I'm typing this out - just heard back from the electrician. 220!

Electricians assume 220 when they see two things.

50 amp service
50 amp outlet


Turbs


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