positve or negative ground

[jojhanv]

hello everyone,

Can anyone possibly tell me what the difference is between a POSITIVE GROUND AND A NEGATIVE GROUND (EARTHING) in the usage for control panels? It's not alarm control panels...it's for electrical control panels for fire pumps. we are using two electrical motors possibly 220V/50Hz or 440V/50Hz depending on the Hp requirement. Do we have a standard which time to use positive or negative ground (earthing)?

thanks very much guys....

 

[sprocketflup]

Canoeboy - Ive found positive earths in some telecommunications equipment (roadside cabinets) before, does that sound right?

I always wondered why they had used them TBH

 

[jojhanv]

Actually the system is for a control panel of a Diesel Engine driven fire pump. the starting system for the diesel engine would be either 12VDC or 24VDC depending on the starter requirement. but the control panel in itself has an AC supply voltage to it. But i don't think that the positive and negative ground is talking about the AC voltage right? so that means without any special considerations I should presumably use the Negative ground for my specifications right?