Surge Suppressor

[SMS]

I have 50 Amp service. Is there a need for a surge suppressor when plugged in to 30 Amp? Will the 50 Amp suppressor work when plugged in to 30 Amp.

[Herk7769]

Yes there is the same need for any service as it protects you from surges and over/under voltages.

When using a 50 amp to 30 amp service adapter, your 50 amp surge suppressor will suppress on the leg that has voltage and alert you that there is no voltage present on the un-powered leg.

[BarryD0706]

When a 50-amp rig is plugged into a 30-amp plug, both legs are powered and the protector will show that (same voltage). Different currents in each leg.

[awwall]

Not enough information SMS. I have a 50amp progressive industries EMS and it works fine in 30 amp hookup when I use my 30 to 50 amp adapter. Tell us a little more about what suppressor you are using.

Essentially, the 30 to 50 amp adapter takes the single 110volts from the 30 amp receptacle and spreads it to the 2 110v poles of the 50 amp plug, thus powering both of your internal 50 amp buses. Be aware that that you will only have 30 amps available and overload may occur at the power outlet on the pole instead of your panel in the motor home.

[SMS]

I didn't want to admit that I am just now looking into buying one. I wanted to be sure that a 50 would take care of my needs. When it comes to electricity, I am dumber than the average bear.

[Herk7769]

Originally Posted by BarryD0706

When a 50-amp rig is plugged into a 30-amp plug, both legs are powered and the protector will show that (same voltage). Different currents in each leg.

Thank you Barry and Wayne. Not owning a 50 amp camper, I was under the impression that a 30 amp pigtail only powered the primary circuit and not the secondary.

Learn something new here every day.

[wmtire]

Originally Posted by herk7769

Thank you Barry and Wayne. Not owning a 50 amp camper, I was under the impression that a 30 amp pigtail only powered the primary circuit and not the secondary.

Learn something new here every day.

Lou, I thought the same thing basically, until we got into a discussion last week about it. That what is so great about these forums......as you said, you learn something new all the time.

[BarryD0706]

Originally Posted by SMS

I didn't want to admit that I am just now looking into buying one. I wanted to be sure that a 50 would take care of my needs. When it comes to electricity, I am dumber than the average bear.

Yes, the current 50-amp units work fine with the 30-amp adapters. I recommend the Progressive Industries EMS units. They're made in USA and have a lifetime warranty.

Lou, this actually happened to me a while back. The 50-amp plug I connected to had a dead circuit. It took me a bit to figure out why half of the stuff in my RV wasn't working. They don't really wire them as primary/secondary. They just share the load. (Park fixed the plug.) I shoulda had my EMS back then!

[Herk7769]

I am trying to wrap my head around this.

The pedestal 50 amp socket is normally wired with two different feeds with each feed being a different phase. That is why measuring across the two hot wires yields 220 volts (110 from each to the neutral).

So what I think you are saying is that with the 30 amp pigtail adapter, the single hot from the 30 amp socket is connected to both of the camper's hot circuits and the Neutral. Since they are the same phase on each leg, no 220 items will work.

It also means that a camper designed with the potential to draw 50 amps on each leg (though alternating between each) is now limited to 30 amps total for both circuits. Did I get that right?

Power management would be really critical I would think.

[BarryD0706]

Lou,
yes, exactly. There are no 220 outlets or appliances in RV's for just that reason. Power management is no different than for any 30-amp RV.

[Herk7769]

Originally Posted by BarryD0706

Lou,
yes, exactly. There are no 220 outlets or appliances in RV's for just that reason. Power management is no different than for any 30-amp RV.

Thanks. I have a switch to select "microwave" or "fireplace" but not both in order to keep my 30 amp camper under 30 amps. My normal summer AC power draw is about 22 amps; but it not unusual to see 28 or 29 amps steady state on the meter.

[BarryD0706]

In case my previous comment led you to the conclusion that you don't need two phases (which is wrong), see this.

[Herk7769]

Originally Posted by BarryD0706

In case my previous comment led you to the conclusion that you don't need two phases (which is wrong), see this.

I think you are over thinking this. With a properly sized 30 amp feed (hot) you only need a similar sized Neutral. There is never an opportunity to get 60 amps since the circuit is just "paralleled" in the adapter. (like hooking up your service line to a string of duplex outlets in the middle instead of an end.)

[BarryD0706]

Yes. The problem can occur only when you have TWO feeds (no adapter) of more than 26 amps each.