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Volts / Amps / HZ

Yahoo Message Number: 82178
Could some of you electricians out there give me a short education.
I use 50amp power - and understand it somewhat. I have a digital meeter plugged into an outlet in the kitchen (Good Governor which shows VOLT and HZ)

Why do the volts go up when I turn on the coffee pot or the front air conditioner. When I turn on the microwave - the volts goes down by 5 to 8 volts. Most campgrounds this does not happen. When it does I get concerned about the electrical equipment in my coach.

I also have a whole coach surge protector which will shut off if volts spike to 130 volts. I have watched when an air conditioner compressor comes on causing the volts to spike to 130 - and ZAP - No power for 5 minutes until the surge protector resets.

Jim in tex

Re: Volts / Amps / HZ

Reply #1 –
Yahoo Message Number: 82179
Jim,

Sounds like a classic bad neutral in the shore power. Might want to have the RV park check it out as it can cause serious damage to your equipment.
Barney

07 Inspire 52059

Sent from my Verizon Wireless 4G LTE DROID

Re: Volts / Amps / HZ

Reply #2 –
Yahoo Message Number: 82180
I agree the park electrical system is what is called soft rather than stiff Bob 06 intrigue 12047

Re: Volts / Amps / HZ

Reply #3 –
Yahoo Message Number: 82181
Jim,

Your 50 amp service consists of 2 hot wires, one neutral and one ground. If your meter is plugged into a 120volt outlet, you then are monitoring only one of the hot legs....apparently the same one that the microwave is also using. That would account for the drop in voltage, although that is way more voltage drop that should be considered normal if the rest of the system is OK.
The fact that the voltage rises when the AC comes on shows that it is connected off the other hot leg. The voltage rise should not happen, in any event, and as Barney has already pointed out, may indicate a poor (loose) neutral OR ground somewhere in the system.
If those symptoms are unique to the campground where you are staying, then the problem probably lies with their system.
If the symptoms follow you around, then suspect the same in your rig. Have someone check the supply side ground and neutral connections for proper torque.

Hope this helps.

Dave Trotter

01 Intrigue 11215

Re: Volts / Amps / HZ

Reply #4 –
Yahoo Message Number: 82182
Jim - 50A power is provided via a transformer connection (power company) in two hot legs plus a center tap (neutral leg). It's 120-0-120 VAC. The neutral leg (center tap) references both of the 50A 120 VAC phases in your circuit breaker box. It's often called line 1 and line 2 with a collection of breakers on each phase. You actually are getting 100A service. Although bus circuit breaker boxes aren't usually connected this way, you could get 240 VAC @ 50A measured across line 1 and line 2. A faulty neutral and/or ground could cause a poor reference which will "pull up" the other phase when a load is applied. As previously mentioned, this could escalate into a dangerous situation for 120 VAC loads not protected from an over voltage situation. It your power guard is popping in this campground but not others, it would suggest a problem in the campground's service entrance connection more than likely. To be sure you'll need to take some additional voltage measurements perhaps from neutral to ground. In a proper system, there should be little to no voltage there. If you do measure potential there a bad connection exists which should be remedied immediately. Perhaps you could move to another site and see what happens. If the whole campground is bad, moving won't matter. Good luck.

At 04:08 AM 9/7/2012, you wrote: