30 Amp / 50 AMP question

[The Danes Are Coming]

Please help me understand this:

When we connect to 30 AMP on a site, all appliances and all electrical outlets are working (although not at the same time if overloaded). 30AMP gives us 1 live wire - L1 and a ground. When we connect to 50 AMP everything is also working and now we can "load the system" even more because now we have 2 live wires - L1 and L2 plus a ground.

In our coach it would appear that, with 50 AMP's, all electric outlets and appliances have been split, in the sense that f.x. half the 110V outlet sockets are using L1 and the other half is using L2.

There must be a device in the the MH that takes care of this, but which is it and how does it work?

[Route 66]

It's not the coach, but the 30 amp adapter.

It connects the 1 30 amp hot wire L1 to both 50 amp hot wires, L1 & L2.

[RustyJC]

The adapter that you use to go from the 50 amp power cord to the 30 amp receptacle handles this by internally jumpering across the L1 and L2 terminals on the 50 amp power cord and feeding them both with the L1 (hot) leg of the 30 amp shore power panel.

Rusty

[The Danes Are Coming]

Sorry guy's - you lost me !!!

[The Danes Are Coming]

... are you saying that everything is wired up for the 50AMP connection but when this is not available my 30 "conversion" plug takes care of "redirecting" things???

[RustyJC]

Yes.

Rusty

[The Danes Are Coming]

Ahhhhh!!!

I have to think about this for while.

[mfire1339]

I believe the auto transfer switch senses L-2 and when plugged to 50 amp.and connects to the intellitec panel.

Mike

[OneRVer]

Quote:

Originally Posted by The Danes Are Coming Ahhhhh!!! I have to think about this for while.

I know what you are thinking. Believe me, I know. The only way I could get this into my thick skull was to take my 50 to 30 amp adapter and an ohm meter and go from point to point.

Now I understand. Have fun.

[wa8yxm]

For simplicity sake I will leave off the safety ground in these diagrams

50 amp service

Black------ L1
White-----Neutral
Red ------ L2

30 amp service

Black ------ L1 (Or L2, you really don't know or care)
White ----- Neutral


30 amp to 50 amp adapter

30 amp side 50 amp side

Black------------Black and Red connected together
White ---------- White

How your EMS works

If Black to Red = zero volts (or less than arbitrary voltage) .. 30 amps

If black to red => arbitrary voltage (say 100) 50 amps

So there is no switching the rig at all.. The "Magic" that provides power to both legs when using a 30 amp cord or a 30 amp adapter is entirely in the adapter/cord.

Though the EMS, if you got one will adjust it's limits per the voltage on the R/B lines.

[Bugzme]

Wow! I thought even though you were on a 30 amp you still got both legs (240 volt). I don't understand why?

[04Crescendo]

On 30 amp, one leg is hot, one neutral, and one ground. 120V total. On a 100 amp, L1 to Neutral (or ground)=120V, L2 to Neutral (or ground)=120V, L1 to L2 = 240V, Ground to neutral = 0V.

[Route 66]

It's all explained here.

[wa8yxm]

"There must be a device in the motor home which takes care of this..."

Actually no..The device that takes care of it is OUTSIDE the motor home.. IT is the dog bone adapter

Your 50 amp plug has 4 wires,, One ground (Forget it) one neutral (Likewise) and two "HOT" (L-1 and L-2)

The 30 amp has only 3 pins on the plug, Ground, Neutral and HOT (Either L-1 or L-2 but to be honest it matters not)

WHen they hook it to the plug.. They jumper the L-1 and L-2 leads in the outlet

ANd thus that (The 50 amp outlet on the 30 amp adapter) is the "Device" that takes care of it.