Electrical hookup Question

wolfe10 wrote:

Bobbo wrote:


I agree that a bad neutral on a 30 amp system doesn't automatically throw 240v through the RV like a 50 amp does, but there are other problems that can be almost as damaging that hit 30 amp units.

I will restate that-- an open neutral on a 30 amp system can NOT put 240 amps-- not possible.

240 requires TWO hots, a 30 amp has but one.

Actually, I think that is what I said. But, I also said there were OTHER problems possible.

And it is 240 VOLTS, not 240 AMPS.

CA Traveler wrote:
Unfortunately it CAN happen and DID happen to me. The problem wasn't an 30A open neutral but an open neutral in the 240/120V CG distribution system which feeds the 120V 30A power.

In my case the problem occurred at night and the PI unit shut down the rig power. I couldn't get the plug out fast enough.

Full function power protectors for 30A power are justified IMHO.

Strange things do happen with electricity. Over power protection is as important as under power protection, as you discovered. Pianotuna is focusing solely on one problem to the exclusion of everything else. If it isn't a bad neutral on a 120v/240v system, he doesn't recognize it as a problem that needs addressing. He couldn't be farther from the truth. It scares me when he tells new folks, adamantly, that a 30 amp system doesn't need the PD EMS. Some of them may believe him.

wolfe10 wrote:

Bobbo wrote:


I agree that a bad neutral on a 30 amp system doesn't automatically throw 240v through the RV like a 50 amp does, but there are other problems that can be almost as damaging that hit 30 amp units.

I will restate that-- an open neutral on a 30 amp system can NOT put 240 amps-- not possible.

240 requires TWO hots, a 30 amp has but one.

Unfortunately it CAN happen and DID happen to me. The problem wasn't an 30A open neutral but an open neutral in the 240/120V CG distribution system which feeds the 120V 30A power.

In my case the problem occurred at night and the PI unit shut down the rig power. I couldn't get the plug out fast enough.

Full function power protectors for 30A power are justified IMHO.

Bobbo wrote:


I agree that a bad neutral on a 30 amp system doesn't automatically throw 240v through the RV like a 50 amp does, but there are other problems that can be almost as damaging that hit 30 amp units.

I will restate that-- an open neutral on a 30 amp system can NOT put 240 volts-- not possible.

240 requires TWO hots, a 30 amp has but one.

On edit-- corrected mistype of amps to volts. Thanks for correction.

pianotuna wrote:
Hi,

I see you are in a 30 amp RV. Take the unit back for a refund. You do not need it. 50 amp rv's DO need that sort of protection because they are on two "legs" of power, and if the neutral wire is loose or faulted in some way then lots of damage can happen.

For 30 amp that is not a possible scenario. Simply check the voltage and polarity before you plug in.

It may be better to look at surge protected autoformers, before using something that cripples the use of the electrical system by cutting off the power at what may be too low a voltage to prevent damage to electric motors. My comfort level is 109 volts or above.

My rig is 30 amp and I have a Progressive Dynamics 30 amp built in unit. It has saved my rig's electronics more than once when power fluctuations happened 2 or 3 days after plugging in. You may not feel one is necessary, but when you tell others they don't need one, you are not doing them any favors. If I had listened to that advice instead of buying mine, I would have replaced my electronics AT LEAST once.

I agree that a bad neutral on a 30 amp system doesn't automatically throw 240v through the RV like a 50 amp does, but there are other problems that can be almost as damaging that hit 30 amp units.

Hi work,

The low voltage I'm comfortable with is not below 108. The unit cuts out at 104 volts. I.E. it is useless for me personally.

In 12 years representing 1200 days of camping, I've never seen voltage higher than 123. Safe zone is 108 to 132 volts. (i.e. plus or minus 10% of 120 volts).

The unit won't protect from a direct lightening strike.

Some autoformers come with surge capabilities. That might be useful to me.

I'd bet that for every person who has a surge device that there are 10 who don't. Yet I see very few comments about damage to 30 amp RV's.

50 amp is a different kettle of fish. They need one--and most folks DO NOT have one. Again there are few reports of damage.

pianotuna wrote:
Hi,

I see you are in a 30 amp RV. Take the unit back for a refund. You do not need it. 50 amp rv's DO need that sort of protection because they are on two "legs" of power, and if the neutral wire is loose or faulted in some way then lots of damage can happen.

For 30 amp that is not a possible scenario. Simply check the voltage and polarity before you plug in.

Really? So what you are saying is low and high voltage won't harm 30 amp service?
Please explain.

This one is easy,,, Actually these two are easy

IF your cord is detachable, Work on the inlet, forget the cord work on the inlet

If the cord is hard wired.. Get the proper pigtale from your dealer or camping world (Either 30 or fifty amp replace the existing cord with the pigtail.

Also get a matching OUTLET and box. Replace On the cord replace the existing RV with the outlet and box (Basically turn the existing cord into an extension cord) It will work fine.

NOTE: if you have an "Inlet" you remove the wires from the inlet.

Put a proper size plug on them and plug into the Powwer monitor.

THis time you use a pigtail with a FEMALE oulet hooked to the inlet

IN both cases you get

Existing cord------(Optional inlet)--Guardian---RV

If Money is no object... A Hughes Autoformer Install kit contains everything you need to do this job. Bit pricy, but it's all in the box.

pianotuna wrote:
Hi,

I see you are in a 30 amp RV. Take the unit back for a refund. You do not need it. 50 amp rv's DO need that sort of protection because they are on two "legs" of power, and if the neutral wire is loose or faulted in some way then lots of damage can happen.

For 30 amp that is not a possible scenario. Simply check the voltage and polarity before you plug in.

You certainly can get low voltage,high voltage and spikes/surges on 30 amp. What I used to do with my portable 30 amp was put a fairly tight fitting padlock on the cord below the male plug, put a piece of chain on that padlock also then wrap the chain around the pedestal and put a padlock on the chain. That secures the device to the pedestal unless someone cuts the cord or the chain.

The 160V occurred at night hours after I plugged in. Without the PI unit it would have been a very expensive night.

Eight years of full timing and my surge protector hasn't been touched, and I've never heard of anyone losing theirs to theft. I did have a friend almost lose his motor home when his built-in model shorted out, so I'll leave mine out and take my chances.