AutoMax
Lifetime Supporting Member
Well, I'll illustrate something you may be unaware of in the UK as I believe even your homes single phase power outlets have two powered legs. In America, our standard power outlets have one energized leg and a "neutral" that is grounded at the service entrance and the utility transformer. It is also not uncommon to find this power structure in our control cabinets. Not only are the loads on these circuits a very common source of noise, if the primary ground to a panel like this becomes compromised everything formerly grounded becomes energized. This is certainly a dangerous situation, but American maintenance electricians (well qualified individuals, anyway) are aware of this. In such a situation the DC- would also begin carrying hazardous loads.
I'm just providing the scenario because you asked...
I'm just providing the scenario because you asked...