Parallel cables
- Thread starter murli8
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Jim W in Tampa
Senior Member
- Location
- Tampa Florida
You dont and its not likely without showing diming
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
murli8 said:
There is another way, sort of. Split the load into two separate halves, and OCP each feeder separately.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Put the conductors in conduit. Protection of conductors is the primary purpose in the life of a conduit.murli8 said:
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
murli8 said:
I'm curious, how is one of the parallel conductors going to "open up".
If you mean disconnected, then it would have to coincidentally disconnect from both ends simultaneously, without touching anything else as it does this. Right, that I would like to witness.
Practically speaking, you are going to have a short to ground (ground fault) or phase-to-phase fault, either of which will most certainly trip the circuit breaker. This is a catastrophic event and if installed and maintained properly, should not occur in the life of the equipment.
I've never seen it done, but I know of no reason you couldn't........if it really really concerns you, you could install "cable protectors" at each end of the cable. They are "cable rated" no "amp rated" and work somewhat like the "fuse" link in automobiles
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Cable limiters would actually cause the condition of one parallel conductor opening.
Cable limiters are usually used to minimize a short circuit on one conductor causing damage to other conductors, that is why they are "conductor and not amp" rated. Typically they are used with parallel runs of 3 or more conductors.
Cable limiters are usually used to minimize a short circuit on one conductor causing damage to other conductors, that is why they are "conductor and not amp" rated. Typically they are used with parallel runs of 3 or more conductors.
beanland
Senior Member
- Location
- Vancouver, WA
Multiple Cables and One Fails
Multiple Cables and One Fails
It can happen. A compression fitting can corrode. A bolted joint can loosen. Even if it does not totally open circuit, I have seen enough cases of one conductor not sharing it's portion of the load. As a result, the other remaining conductors carry more than their rating. Eventually, something overheats and fails.
You can get fancy with protective schemes, zero sequence CTs on each cable run, etc. This is a case where periodic infrared imaging will hopefully catch the problem before a failure occurs.
Multiple Cables and One Fails
It can happen. A compression fitting can corrode. A bolted joint can loosen. Even if it does not totally open circuit, I have seen enough cases of one conductor not sharing it's portion of the load. As a result, the other remaining conductors carry more than their rating. Eventually, something overheats and fails.
You can get fancy with protective schemes, zero sequence CTs on each cable run, etc. This is a case where periodic infrared imaging will hopefully catch the problem before a failure occurs.
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