Question for those with EMS-HW50C

Good catch BlindGuynAR. Most of us did miss that very important point. I was very surprised the tech was giving the advice he did until you pointed out the error of my thinking.

BlindGuynAR wrote:


The Support tech was spot on with his/her advice.

He sure was and they were quick with a response too. I asked the question on Sunday night and got a reply the same day.


That's pretty impressive these days too.

Everyone is thinking he can use an adaptor, but he can't. I assume he has a 30amp cord on that 30 amp trailer so adaptor will not work unless he changes to a 50 amp shore cable.

You don't have to do anything every time. The ems-hw50c is the hard wire unit that sits inside trailer not at the pedestal. During install just wire a 3 in jumper wire from your one hot from 30 amp to the second hot you would normally have with 50 amp.

Now EMS will "think" it as two legs of power and function. Nothing will be connected to the output of the second leg, but the EMS will allow the leg one through allowing your 30 amp shore power cord to power your 30 amp breaker box.

Nothing to do when pluging in cord. Leg 1 will show all your usage on the remote display for 30 amp and leg 2 will show the volts/hz = leg 1 and all outputs for leg 2 will show zeroes.

Use it 100% of the time wired always with the jumper until you upgrade. When you upgrade to 50amp in trailer the jumper won't be required as you'll have new cord, wire, breakers, and such.

The Support tech was spot on with his/her advice.

No your 30 amp to 50 amp does that for you. I use mine even when we only have a 30 amp service. :)

Roger10378 wrote:
No. The adapter puts 120V on each side. If it didn't only half of your stuff would work. If you don't jumper the two sides together it will not work as it would see low voltage on the second side and shut everything down.

OK, this is consistent with the manufacturer's jumper suggestion as well. Now I understand the details as to why as well :-)


I guess most RVs with 50A service don't have any 220V appliances so having both legs with the same phase works fine.

No. The adapter puts 120V on each side. If it didn't only half of your stuff would work. If you don't jumper the two sides together it will not work as it would see low voltage on the second side and shut everything down.

Good news.

These 30A adapters are only delivering 120V to your RV right. So the EMS is seeing 120 Volts on one side an zero (open circuit) on the other.

Mandalay Parr wrote:
No no no

The 50 to 30 amp adapter takes care of it.

X2

Nope, ours is a 50 amp system and we have the EMS-LCHW50 from Progressive Industries. We spend three months every winter with a 30 amp hook-up. Just plug in with a dog bone adapter and no problem. The EMS works just like it does when we are plugged into 50 amp. It has also found a couple of mis-wired 30 amp posts over the years.

No no no

The 50 to 30 amp adapter takes care of it.

Call me if you wish.