50 amp electrical question

[OnTheGo]

A protective device between the RV and the campsite's 50 amp receptacle would not let current pass through to the RV. One leg was metered at 128vac, and the other was 123vac. I don't know if the readings were at the receptacle or the device.

I was brought into the situation with a phone call and ended up telling the caller I couldn't help him. Is it okay to have a 5v difference and be considered usable in a 50 amp circuit?

Also, what is the highest AV voltage allowable? ... never had to consider it before. All my concerns have been low voltage.

I'm curious why the device wouldn't allow current into the RV.

[Jagiven]

What device do you have? Not sure if all the EMSs work the same, when monitoring high voltage.

Somewhat related, but not really, but interesting at least to me about the history of electricity:

I was in a "lunch and learn" meeting at work (engineering firm). Electricity was the subject matter. The presenters were from the local utility company, presenting on project management for a new power plant.

They started off with a bit of history of the early electrical grids, and how we got to AC power we use today. They discussed that in 1892 the "standard" started off at 55Vac, then jumped up to 110V, due to the Arc lights that were being used, and everyone used two in series (110V). Then in the 30's it had crept up to 115V. In 1984 the official US voltage was bumped to 120V. They stated it is creeping up again, they are working towards 130V. I do not recall the timeline. They stated they are required to provide the electricity +/- 5% of 120V so that means between 114V and 126V.

[Robbbyr]

Originally Posted by OnTheGo

A protective device between the RV and the campsite's 50 amp receptacle would not let current pass through to the RV. One leg was metered at 128vac, and the other was 123vac. I don't know if the readings were at the receptacle or the device.

I was brought into the situation with a phone call and ended up telling the caller I couldn't help him. Is it okay to have a 5v difference and be considered usable in a 50 amp circuit?

Also, what is the highest AV voltage allowable? ... never had to consider it before. All my concerns have been low voltage.

I'm curious why the device wouldn't allow current into the RV.

There are more issues than just voltage that can prevent an EMS from connecting. My Progressive Industries hardwired EMS shuts off the incoming feed if it detects reverse polarity, open neutral, open ground, frequency outside of certain limits, and 240-volt protection.

Did the caller's unit list any errors? How long did they wait for it to connect? My PI unit has a built-in delay before it connects, I can select either 15 seconds or 136 seconds.

[Lake Huron]

Originally Posted by Jagiven

What device do you have? Not sure if all the EMSs work the same, when monitoring high voltage.

Somewhat related, but not really, but interesting at least to me about the history of electricity:

I was in a "lunch and learn" meeting at work (engineering firm). Electricity was the subject matter. The presenters were from the local utility company, presenting on project management for a new power plant.

They started off with a bit of history of the early electrical grids, and how we got to AC power we use today. They discussed that in 1892 the "standard" started off at 55Vac, then jumped up to 110V, due to the Arc lights that were being used, and everyone used two in series (110V). Then in the 30's it had crept up to 115V. In 1984 the official US voltage was bumped to 120V. They stated it is creeping up again, they are working towards 130V. I do not recall the timeline. They stated they are required to provide the electricity +/- 5% of 120V so that means between 114V and 126V.

Now that is interesting. What's more interesting is why the jump up to 130v?
Conspiracy theory; since people are using more "energy saving" devices the power companies dont have to produce as much so they aren't making as much so they in turn bump it up and make people use more?
Wonder if that bump will make LED lights burn brighter which in turn makes them burn out faster? Lol!

[RPR]

What device was it that he was using between the RV and power receptacle? Was it check to see if was not bad? Voltage readings were within limits.

[OnTheGo]

... refering to OP: I was cold called, knew right away I couldn't help, and ended the call quickly. So I don't have any information about the device (EMS?) being used by the trailer owner.

They were concerned only about voltage. If there were other conditions they were either unaware of them (hopefully the device would have made an indication) or didn't know what they were.

[Vicr]

This is a document that issues a national standard for utility voltage tolerances.

[OnTheGo]

Thank you, Vicr. It might have been blocked for high voltage.

[craigav]

A Progressive EMS stops the flow of power outside of 104~132 volts. It is not overly uncommon to see voltage differences between the two legs, what happens is many campgrounds (that I have used) seem to pull more current off of one leg than the other, perhaps they ran too many 30a receptacles off of the same leg or otherwise didn't distribute the load as evenly as they could have. I have seen even 10v differences between the legs, but that didn't keep things from running, assuming of course the voltage is still sufficient, say 110v on one leg and 120v on the other.

[thenne1713]

From my experience, This TYPE of imbalance is usually due to a NEUTRAL corrosion/ connection problem, maybe even back on the POLE TRANSFORMER, E.g. aluminum overhead/ underground UTILITY wiring? I would want to inspect CG site box/ receptacle connections, and verify voltages at CG Breaker, and if all appeared good, call and discuss w/ local utility provider, or place service request to catch problem NOW? I really am surprised that this low DELTA is blocked by EMS system, but it maybe a common/ known issue that this reflect BIG problem under LOAD, BUT 4.5v maybe trigger, or meter error and diff= greater than?

[TnHiker]

Originally Posted by Lake Huron

Now that is interesting. What's more interesting is why the jump up to 130v?
Conspiracy theory; since people are using more "energy saving" devices the power companies dont have to produce as much so they aren't making as much so they in turn bump it up and make people use more?
Wonder if that bump will make LED lights burn brighter which in turn makes them burn out faster? Lol!

Higher voltage is not a bad thing to a point. The higher the voltage the lower the amp draw will be. That allows for the wire to heat less because of the lower current passing through it. Amperage = watts divided by voltage. Happy Camping and God Bless.