DC power circuit protection
DC power circuit protection
(OP)
We have a large 125VDC source that feeds control relays, indicating lights, power relays, etc. I notice on the control schematics that in some cases both the (+) and the (-) are protected by a fuse or circuit breaker, but in other cases, particularly on the negative side of a coil or an indicating lamp the (-) side is not fused.
And,
We're installing a new computer cabinet that has a new power supply converting to 24VDC that is fed from this 125VDC source, and I notice the engineer didn't fuse the incoming negative wire, but did the positive. The positive side of the 24VDC is fused. The negative side of the 24VDC supply is connected to ground, so I'm sure that is why this side isn't fused. Ok.
This inconsistenty is confusing...can anyone clear this up?
And,
We're installing a new computer cabinet that has a new power supply converting to 24VDC that is fed from this 125VDC source, and I notice the engineer didn't fuse the incoming negative wire, but did the positive. The positive side of the 24VDC is fused. The negative side of the 24VDC supply is connected to ground, so I'm sure that is why this side isn't fused. Ok.
This inconsistenty is confusing...can anyone clear this up?






RE: DC power circuit protection
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: DC power circuit protection
On further examination, the 125VDC source is derived from 60 batteries in series together. I don't see where it's connected to ground on the negative side. Therefore, we have an ungrounded system. For consistency sake wouldn't it seem prudent to fuse both the positive and the negative to all loads?
RE: DC power circuit protection
Bill
--------------------
"Why not the best?"
Jimmy Carter