Norcold 1200 operates without ground connected

[kmb1966]

I have been working on my Norcold 1200 again and have noticed that the unit will power up and operate when only connecting the 12 volt (+) supply to the rear control board connector labeled "12V". The connector labeled GND can be disconnected totally. Obviously there refrigerator is somehow already grounded somewhere, but I am wondering if this is a problem or is normal??

[kmb1966]

enblethen wrote:
It is normal to have metal pipe grounded to stop any potential (or at least reduce the chance) arcing.
It could be a higher resistance then a good solid ground connection via a copper wire.

yes. I have it re-connected to the ground wire.
I was re-connecting everything when I noticed that if I connected the 12V before the ground wire, the propane igniter engaged and the burner lit. I now have the GND connector on the ground copper wire again.

[enblethen]

It is normal to have metal pipe grounded to stop any potential (or at least reduce the chance) arcing.
It could be a higher resistance then a good solid ground connection via a copper wire.

[wnjj]

opnspaces wrote:

kmb1966 wrote:
I have been working on my Norcold 1200 again and have noticed that the unit will power up and operate when only connecting the 12 volt (+) supply to the rear control board connector labeled "12V". The connector labeled GND can be disconnected totally. Obviously there refrigerator is somehow already grounded somewhere, but I am wondering if this is a problem or is normal??

I think you all missed the question "Is this a problem or is it normal?".
No it is not normal which you can gather from all the responses trying to help you figure out how it's possible. But is it a problem? Probably not but I guess that's where you have to define your meaning of the word problem. Should the actual ground be fixed or attached? Absolutely.

Sounds to me like it is normal to have grounded copper piping. The OP has the ground wire disconnected and intends to put it back so also no problem that I can see.

[opnspaces]

kmb1966 wrote:
I have been working on my Norcold 1200 again and have noticed that the unit will power up and operate when only connecting the 12 volt (+) supply to the rear control board connector labeled "12V". The connector labeled GND can be disconnected totally. Obviously there refrigerator is somehow already grounded somewhere, but I am wondering if this is a problem or is normal??

I think you all missed the question "Is this a problem or is it normal?".
No it is not normal which you can gather from all the responses trying to help you figure out how it's possible. But is it a problem? Probably not but I guess that's where you have to define your meaning of the word problem. Should the actual ground be fixed or attached? Absolutely.

[Chris_Bryant]

Those fuses failing is fairly common, the holder gets loose and/or corroded, and the ~300-450 watts continuos heats them up.
Checking fit and a bit of dielectric grease eliminates the problem.
The real tricky problem with the glass fuses is if they heat up the element can come unsoldered from the end cap- fuse looks good visually but doesn’t conduct.

[DFord]

Those fuses carry 120v to the heating elements. If the heating elements short out, the fuse should blow. There's one for each element in the 1200 model.

[mchero]

Another issue I had with the 1200, and possibly other models;

AC side of my 1200 died one afternoon. I found that the AC glass fuse holder on one side had a bad connection that started heating up melting the solder on the board. The connector failed. Ended up purchasing a new board at 100 plus smackers!

Found this;

on the web and was able to get the board back to 100%
Now I have a spare!

[larry_cad]

Probably not a good idea to have electricity flowing through a pipe that is carrying flammable gas

[kmb1966]

vermilye wrote:
Do you have copper propane piping? One of my refrigerators ran on the hot & the propane copper pipe until the broken ground was discovered.

yes. that has to be how it is being grounded.

[ScottG]

Chris Bryant wrote:

vermilye wrote:
Do you have copper propane piping? One of my refrigerators ran on the hot & the propane copper pipe until the broken ground was discovered.

^^^^^^^ This ^^^^^^^

Yup, he nailed it!

[Chris_Bryant]

vermilye wrote:
Do you have copper propane piping? One of my refrigerators ran on the hot & the propane copper pipe until the broken ground was discovered.

^^^^^^^ This ^^^^^^^

[vermilye]

Do you have copper propane piping? One of my refrigerators ran on the hot & the propane copper pipe until the broken ground was discovered.

[BB_TX]

Is the refrigerator metal frame in any way touching the trailer metal frame? Trailer frame is ground, and the fridge internal 12 v ground may also be connected to the refrigerator frame.

[enblethen]

It is possible that one of the screws holding the circuit board has a ground connection.
The 120 volt element could be going to ground