Fridge Power Problem or Not

[sealevel_ram]

My motorhome is plugged into 30 amp power in my garage. Have been running microwave and air conditioning for check out.

Today I turned on my Norcold. It runs fine on LP, but when I turn it on electric, my Intellitec EMS goes up to 40 plus amps for a second and then to zero. The load shedding lights go out, and the fridge says "NO AC". (Of course, I don't have any other draws such as the air conditioning activated.)
I turn on the generator and the fridge runs OK on the 50 amp AC.

I know the fridge should not draw 40 amps at start. Fridge problem? Works fine with gen power. Maybe the EMS is not performing as it should. Any ideas?

[DrewE]

MrWizard wrote:

sealevel ram wrote:

MrWizard wrote:
i would suspect a bad 120v heater element leaking to ground aka the metal tube of the heater

you can turn off the ems, or you can pull out the heater element and test it for resistance between the shell/case and the power leads

it should read infinity on the ohms scale any lower reading and its defective

Wouldn't it be bad under generator power also?

The generator does not have a neutral to ground bond
Without the bond, there is no neutral to hot short detected because of leakage

It's a simple test.. pull the heater and test it with the meter

Chris is probably right, EMS problem, not really 40 amps

If it's a built-in generator on the motorhome, it should have a neutral to ground bond (that is switched in with the transfer switch). If it's an external portable generator, it generally would not be bonded. If there's an inverter in the mix, things get that much more complicated.

If the heater element has a hot to ground short (as opposed to a neutral to ground short), what you suggest does make sense. A slow-blow fuse, for example, might be slower than the EMS/circuit breaker in detecting problems. (A GFCI would probably be even quicker).

At any rate, testing the fridge element seems like a decent place to start troubleshooting. It is a relatively common failure mode, after all.

[sealevel_ram]

Old-Biscuit wrote:
Are you running microwave, A/C Unit while attempting fridge on AC?

As my original post stated, no other circuits are on when I try the refrigerator.

[Old-Biscuit]

Are you running microwave, A/C Unit while attempting fridge on AC?

EMS is load shedding cause there is only 30A supply.......

Have you tried just fridge w/o anything else on.......turn off all ac circuit breakers except for fridge?

Isolate issue! One circuit breaker at a time.

[MrWizard]

sealevel ram wrote:

MrWizard wrote:
i would suspect a bad 120v heater element leaking to ground aka the metal tube of the heater

you can turn off the ems, or you can pull out the heater element and test it for resistance between the shell/case and the power leads

it should read infinity on the ohms scale any lower reading and its defective

Wouldn't it be bad under generator power also?

The generator does not have a neutral to ground bond
Without the bond, there is no neutral to hot short detected because of leakage

It's a simple test.. pull the heater and test it with the meter

Chris is probably right, EMS problem, not really 40 amps

[Chris_Bryant]

I would guess it's an EMS problem- there is a 5 amp fuse on the refrigerator that would blow well before you hit 40 amps.

[sealevel_ram]

MrWizard wrote:
i would suspect a bad 120v heater element leaking to ground aka the metal tube of the heater

you can turn off the ems, or you can pull out the heater element and test it for resistance between the shell/case and the power leads

it should read infinity on the ohms scale any lower reading and its defective

Wouldn't it be bad under generator power also?

[MrWizard]

i would suspect a bad 120v heater element leaking to ground aka the metal tube of the heater

you can turn off the ems, or you can pull out the heater element and test it for resistance between the shell/case and the power leads

it should read infinity on the ohms scale any lower reading and its defective