Community Forums

BigBen1 · 03-14-2016, 03:24 PM

Hello Everyone!!!

First post in this forum but have been reading for some time, great group here!

So I am fairly knowledgeable about electrical wiring 50a and 30a.

My RV is wired for 50A. Sometimes I go to parks that only have 30A.
When I am using my 30A (male) to 50A (female) adapter cable only half of my appliances work. I know why this occurs it is because half my appliances are on the "HOT1" bus and the other half on the "HOT2" bus.

My question is do I just have a crappy adapter cable? Shouldn't a good well made cable take the single hot 30a output and split the output to the 2 hot leads of the 50a inlet? Obviously I need to mindful and careful not to overload the 30a circuit but I am well capable of doing that.

Currently i am popping my dist panel open and moving around the breakers between the HOT1 and HOT2 as needed but that is far from ideal.

Irrelevant but curious question number 2: When running on 30a service the way I am currently couldn't i just jumper the two HOT buses (1 and 2) as an alternative to swapping breakers around? Obviously have to be carefully to disconnect that jumper before running on a true 50a otherwise would be seeing sparks flying out of all my appliances from the 240V blast!!! LOL

thanks for the advise!

thebings · 03-14-2016, 03:30 PM

Sure sounds like a bad adapter cable to me. You could plug the adapter cable into the 30amp post and see if you have 115volts to each side of the 50amp end of the adapter.

Skip426 · 03-14-2016, 03:32 PM

Welcome to iRV2.

Test your adapter cable with a voltmeter the same way you would a park plug.
I think you'll find it's junk. Or at the least a very poor connection for the one leg.
When ever I'm in a 30 amp site using an adapter, for my 50 amp coach , everything works.

**Lt Dan** · 03-14-2016, 03:37 PM

Quote:

Originally Posted by BigBen1

My question is do I just have a crappy adapter cable? Shouldn't a good well made cable take the single hot 30a output and split the output to the 2 hot leads of the 50a inlet? Obviously I need to mindful and careful not to overload the 30a circuit but I am well capable of doing that.

Some of the cheaper 50 to 30amp adapters do not have a built in jumper for both legs of the 50amp service and only power one side. I know because I had one and had the same problem you do. I bought a better quality adapter and it powers both legs of the 50 amp. As skip said, it's easy to test with a volt meter, or use an ohm meter to test continuity.

Just my findings, others may vary.

Arch Hoagland · 03-14-2016, 03:42 PM

Year, make and model of your RV would help us to help you.

Old-Biscuit · 03-14-2016, 03:47 PM

30A to 50A adapter SHOULD have jumper from the 30A hot to both 50A hot leads.

Plug just the adapter into 30A power receptacle and then measure if both leads on 50A end of adapter are hot.....easy and simple test

FlyingDiver · 03-14-2016, 04:12 PM

Quote:

Originally Posted by Arch Hoagland

Year, make and model of your RV would help us to help you.

He's got a 50amp/240V shore power cord. What other info could you possibly need for this issue?

l1v3fr33ord1 · 03-14-2016, 04:16 PM

Hey BigBen-

BigBen1 · 03-14-2016, 04:29 PM

Ahh perfect so a good quality adapter SHOULD jump the 2 x 50amp HOT leads mine just must be crap..... I definitely only have power on one of the leads.

Good I don't have to make my own!

Any recommendations for a good brand/manufacturer?

BigBen1 · 03-14-2016, 04:38 PM

Are there any y-adapters which can say take 2 x 30a (or 30a and 15a) and output to a single 50a plug.

In effect sending one of the 30a input down HOT1 lead and the other 30a input down the HOT2 lead of the 50a plug?

I have a y-adapter which has 1 x 30a and 1 x 15a input but it always trips the GFCI is it because they share the neutral? Or maybe the y-adapter is just not wired as i said above?

Old Scout · 03-14-2016, 04:59 PM

You can read up on this topic for several nights--based on what has already been written on this forum. "Normally," a 30 to 50 amp adaptor will provide/share a single leg of 30 amps from pedestal to the two "hot" legs on your coaches 50 amp service [really 100 amps, 50 on each leg]. The two legs are separate in your coach [eg no 240v appliance], so no real chance of 240v getting in your coach. When you start trying to combine multiple legs of different amps and phases, the risk increases. Two things are certain[IMHO]: 1- GFCIs dont like motor homes; and 2-get yourself a good surge protector in your coach to protect you from: 240v, surges, reverse polarity, etc. I like Progressive Industries products--lifetime warranty, enough said....

BigBen1 · 03-14-2016, 04:59 PM

Nevermind! Found my answer to this question!

If the 2 x 30a (or 1 x30a and 1 x15a) outlets are on completely different circuits then its fine (like 2 separate pedestals) if not it will trip the GFCI because your tying the neutrals together.

http://www.irv2.com/forums/f44/30a-t...r-77318-4.html

gemini5362 · 03-15-2016, 10:08 AM

Quote:

Originally Posted by Old Scout

You can read up on this topic for several nights--based on what has already been written on this forum. "Normally," a 30 to 50 amp adaptor will provide/share a single leg of 30 amps from pedestal to the two "hot" legs on your coaches 50 amp service [really 100 amps, 50 on each leg]. The two legs are separate in your coach [eg no 240v appliance], so no real chance of 240v getting in your coach. When you start trying to combine multiple legs of different amps and phases, the risk increases. Two things are certain[IMHO]: 1- GFCIs dont like motor homes; and 2-get yourself a good surge protector in your coach to protect you from: 240v, surges, reverse polarity, etc. I like Progressive Industries products--lifetime warranty, enough said....

I agree with you on the Progressive industries unit. I would caution that it makes a difference which model you have. The one that came on my 2005 coach went out and it was made before they went to the lifetime warranty. I had to pay for the new one.

Kiawah · 03-18-2016, 08:34 PM

Quote:

Nevermind! Found my answer to this question!

If the 2 x 30a (or 1 x30a and 1 x15a) outlets are on completely different circuits then its fine (like 2 separate pedestals) if not it will trip the GFCI because your tying the neutrals together.

Not true, let me explain. A GFCI plug, monitors the current on the positive leg, with the current coming back on the neutral line, and if they are different it will trip the breaker.

When you try to use an adapter that has a 30amp input and a 15/20 amp input, they must tie the two neutrals together for the single neutral output. When that happens, either some of the 30Amp current will come back on the 20Amp GFCI neutral (and trip the breaker).....or some of the 20amp current will go back on the 30amp neutral (and also trip the breaker).

Doesn't matter if you are using two different pedestals off the same transformer, or even two different transformers. It is the mismatch between the current in the GFCI which will trip the GFCI breaker.

I doubt that you'll find a pedestal that has a 15/20 that is NOT a GFCI breaker.