Park Voltage changes with load (50) amp version

[wolfe10]

Originally Posted by theoldwizard

They do sell certain types of 4 wire cable with a smaller neutral, but that can only be used after some careful load analysis. The basic assumption is that there are few 120V loads and 240V load usually (always ?) pull equally.

No, the reason one can "get by" with a smaller-gauge neutral is that the neutral on a 50 amp circuit only carries the DIFFERENCE in load between L1 and L2.

And, would like for someone to post a link to a current electrical code that calls for a ground except at the main CG breaker box.

[nothermark]

In the typical American system there is no need for a neutral connection for 240 VAC. The power is drawn from each end of the power pole transformer with no neutral needed but the safety ground is in place. There may be a lug for neutral or their may be a timer or similar small load on one leg.

I've seen installers go nuts over that when confronted with European origin spa heaters. They use ~240 as their basic distribution so there is no neutral connection point. That leaves a spare wire that causes some interesting conversations. ;-)

[Sbrownstein]

Originally Posted by wolfe10

...And, would like for someone to post a link to a current electrical code that calls for a ground except at the main CG breaker box.

You are kidding...right?

[theoldwizard]

Originally Posted by wolfe10

No, the reason one can "get by" with a smaller-gauge neutral is that the neutral on a 50 amp circuit only carries the DIFFERENCE in load between L1 and L2.

That was what I was trying to say ! Thanks for clearing it up !!

[theoldwizard]

Originally Posted by nothermark

In the typical American system there is no need for a neutral connection for 240 VAC.

There may be "no need" for true 240V loads, but the NEC has been changed to say that pretty much ALL 120V AND 240V residential outlet must have both neutral and a ground wire in the switch box and in the outlet/fixture.

You can not buy a a 3 prong oven/dryer plug/outlet any more.

[nothermark]

Originally Posted by theoldwizard

There may be "no need" for true 240V loads, but the NEC has been changed to say that pretty much ALL 120V AND 240V residential outlet must have both neutral and a ground wire in the switch box and in the outlet/fixture.

You can not buy a a 3 prong oven/dryer plug/outlet any more.

I'm not quibbling over code. I am talking about what is needed.

Don't need to buy a 3 prong as I have a box full. Does leave me wondering what other folks with old equipment do. ;-)

[Sbrownstein]

There still is an exception in the code that allows the use of existing 3 prong outlets. You buy a 3 prong pigtail and continue to feed even 4 wire appliances with the 3 wire cord. You can still get 3 wire pigtails and there is a jumper in most dryers for this method.

[ralph0808]

Ok guys I still the problem and I think it is inside the RV somewhere!! I have the grounding rod installed and it made no difference. I then returned to the water heater which was part of the problem. The dealership Service Manager told me 1/06/15 when I purchased it that he personally changed the electric element, and it was a 2000 watt on a 15 amp circuit. I put a 1500 watt element in today because of high current loading on leg L1. But the voltage swing continues with one going high 127-129 volts while the other maybe 111-115 or even down to 109. So I have crawled around inside the beast and checked every screw for every wire in the hard wired TRC 40250-RVC surge guard. I have checked the connections for the inverter, the main panel, sub panel, checked the power cord and cleaned the pins on the plug. The surge guard was replaced in 4/15 at a different dealership under extended warranties. So I don't know what to check next. I have the PT50 plugged in at pedestal saying E-0 and giving the same voltages that I have with digital meters and also two DVM that are usually within a volt or two difference. So what's next??

[firedoc]

Are you saying you have tested the plug with a volt meter and it passes this test


14-50R

The voltage between Y and X should be 240-Volt, X and W 120-Volt, Y and W 120-Volt, X and G 120-volt, Y and G 120-volt, W and G 0-Volt

[firedoc]

Oops picture didn't load

[firedoc]

Here is a better diagram

[ralph0808]

Well actually I am measuring voltage and current at connection points of L1 & L2 at the main panel with some digital meters capable of reading voltage on top display and current with a coil around the wire. I have also verified the values and compared them with a clamp on current meter and a digital DVM. So for instance just had L1 with 124 volts & .2 amps with L2 with 121 volts & 7.7 amps. The wife put a hair dryer on high to L1 116 volts & 13.5 amps L2 125 volts 7.2 amps. This is only a slight change in comparison to bigger loading or AC turning on while cooking.

[ralph0808]

But yes at the pedestal that is now pretty close to what I had measured there yesterday.

[ralph0808]

243 across the hots with 121 or 122 to neutral and ground. O volts between W and G,