manhole grounding requirement
manhole grounding requirement
(OP)
Just want to reassue my understanding of the requirement of bonding/grounding in manholes. My understanding is the requirement is only applicable if splicing of cables is done inside the manhole, and where the manhole is used only for pull-thru of the cable, there is no bonding requirement in that manhole, including any metal steps, etc. Is that statement correct?






RE: manhole grounding requirement
RE: manhole grounding requirement
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: manhole grounding requirement
RE: manhole grounding requirement
Alan
----
"It's always fun to do the impossible." - Walt Disney
RE: manhole grounding requirement
RE: manhole grounding requirement
RE: manhole grounding requirement
Generally, if there is any metal part that is in the same compartment and it is not intended to be energized - it should be grounded. It means that if you have supporting structures for the cables in the pull-thru manhole they should be grounded to a local ground. In some jurisdictions even the manhole covers are grounded. The ground resistance must be within a local regulations requirements.
RE: manhole grounding requirement
RE: manhole grounding requirement
Medium voltage cable is normally shielded, so an insulation failure would result in current flow between the conductor and shield. Normally that results in a nearly instantaneous trip of your overcurrent protection.
For medium voltage cable, the greater hazard is that the ground connection(s) to the shield could be broken which could cause the shield to become energized. In most installations the shield is grounded at at least two locations.
Alan
----
"It's always fun to do the impossible." - Walt Disney
RE: manhole grounding requirement