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realRVvilla · 06-13-2011, 01:10 PM

I just checked into a park in Perris, Ca. and when I asked about the fact that (1) the power pedestal is 50 amp connection, we only have 30 amps and (2) the ac voltage meter inside our coach shows about 132 and did they know it was too high. My answer was that the voltage is increased in the summer to allow for air conditioners to run, and someday they will have 50 amps so they installed those instead of 30 amp pedestals. Are parks able to up the voltage according to season?

RJay · 06-13-2011, 01:22 PM

Whether the park can increase the voltage isn't the problem, 132 volts is too high. Surge protectors are designed to trip at that level and can do damage to your equipment. Raising the voltage during high demand is a common procedure but it is normally raised to only 126-127 volts, not 132 volts.

FlyingDiver · 06-13-2011, 01:29 PM

Quote:

Originally Posted by realRVvilla

I just checked into a park in Perris, Ca. and when I asked about the fact that (1) the power pedestal is 50 amp connection, we only have 30 amps and (2) the ac voltage meter inside our coach shows about 132 and did they know it was too high. My answer was that the voltage is increased in the summer to allow for air conditioners to run, and someday they will have 50 amps so they installed those instead of 30 amp pedestals. Are parks able to up the voltage according to season?

Not sure I understand your comment about 50 vs 30 amps. Is it a 30 amp (3 connector) outlet with a 50 amp breaker? Or a normal 50 amp outlet and breaker? Or something else?

It's my understanding that nominal 120v can be +/- 10%, so the allowable range is 108 to 132. They're right at the high limit, but not really out of spec. I do normally see 124 or so at most campgrounds that aren't overloaded.

joe

RJay · 06-13-2011, 01:42 PM

The NESC normal distribution voltage range is 120 volts +/- 5% not 10%.

FlyingDiver · 06-13-2011, 02:06 PM

Hmm. Maybe 10% was the range my EMS allows before it trips.

joe

Tom Cook · 06-13-2011, 02:20 PM

Raising the voltage is a cheap way to avoid using the proper wiring to handle the load. AC compressors are expensive but why would the park owner care?

RJay · 06-13-2011, 02:37 PM

Hi Joe,
I'm not aware the EMS trips at a particular voltage level. I think you might be getting the EMS confused with the surge protector. The surge protector has strange cutoff voltage limits with 132 volts AC on the high side and 104 volts AC on the low side. This is for the Progressive Industries unit. At 132 volts AC is where control boards and some electronics can be damaged.

realRVvilla · 06-13-2011, 03:06 PM

it is a 50 amp connector, but our panel shows amps used which only happens when we are on 30 amps.

FlyingDiver · 06-13-2011, 03:14 PM

Quote:

Originally Posted by RJay

Hi Joe,
I'm not aware the EMS trips at a particular voltage level. I think you might be getting the EMS confused with the surge protector. The surge protector has strange cutoff voltage limits with 132 volts AC on the high side and 104 volts AC on the low side. This is for the Progressive Industries unit. At 132 volts AC is where control boards and some electronics can be damaged.

I have a Progressive unit as well. They refer to their products as EMS units. I know it's not the same as the coach EMS. I don't like to refer to the Progressive as a surge protector, because it's more than that.

joe

FlyingDiver · 06-13-2011, 03:15 PM

Quote:

Originally Posted by realRVvilla

it is a 50 amp connector, but our panel shows amps used which only happens when we are on 30 amps.

Sounds like it's wired wrong, which is a really dumb thing to do.

joe

RJay · 06-13-2011, 03:17 PM

What parks sometimes do to wire a 50 amp plug is to wire the other prong of the receptacle with the same phase. So if you were to take voltage readings at the pedestal 50 amp receptacle you would get 120 volts from one live leg to neutral, 120 volts to the other live leg(two live legs for 50 amps) and 0 volts across the two live legs instead of 240 volts.

Gary - K7GLD · 06-13-2011, 03:19 PM

I'd bet that in spite of that 132 volts at the pedestal, the ACTUAL voltage at the A/C itself is down around 125 after wiring losses between the pedestal and the A/C...

*I* sure wouldn't lose any sleep over it...

.

RJay · 06-13-2011, 03:25 PM

I would until I measured it. It's not the A/C's that I'd be concerned with as motors prefer higher voltage than lower. I'm concerned with refrigerator control boards and the like.

FlyingDiver · 06-13-2011, 03:27 PM

Quote:

Originally Posted by RJay

What parks sometimes do to wire a 50 amp plug is to wire the other prong of the receptacle with the same phase. So if you were to take voltage readings at the pedestal 50 amp receptacle you would get 120 volts from one live leg to neutral, 120 volts to the other live leg(two live legs for 50 amps) and 0 volts across the two live legs instead of 240 volts.

Which is certainly wired incorrectly.

joe