AlbertL57
Member
- Location
- Falls Church, VA
- Occupation
- Solar maintainer
No supplier seems to stock them, and they're quoting lead times of 6 months or more. Does anyone know what happened to that supply chain?
Cable limiter availability?
- Thread starter AlbertL57
- Start date
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
What’s a cable limiter?
-Hal
-Hal
Julius Right
Senior Member
- Occupation
- Electrical Engineer Power Station Physical Design Retired
ramsy
Roger Ruhle dba NoFixNoPay
- Location
- LA basin, CA
- Occupation
- Service Electrician 2020 NEC
- Location
- New Jersey
- Occupation
- Journeyman Electrician
These are what ConEd specified. A little sloppy IMO but this was installed by their sub-contractor.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
No.
Usually, they are intended to open a faulted cable in a parallel set of conductors. They are not designed to be used as a backup OCPD.
I don't think I have ever seen a trip curve for a cable limiter. Without knowing its opening time you would not be able to calculate the resultant incident energy.
PaulMmn
Senior Member
- Location
- Union, KY, USA
- Occupation
- EIT - Engineer in Training, Lafayette College
I'm mystified. How are these different from a fuse or circuit breaker? The spec sheet appears to only deal with wire size, and doesn't mention current... How does it -know- it's time to open the circuit?
AlbertL57
Member
- Location
- Falls Church, VA
- Occupation
- Solar maintainer
Yes, it does seem mysterious! You're correct - they are rated only by wire size and material (e.g. 250MCM Cu). Internally, they must have some kind of fuse element, apparently rated only on the basis of preventing the wire or insulation from melting.
AlbertL57
Member
- Location
- Falls Church, VA
- Occupation
- Solar maintainer
Here's a similar service from Pepco in Washington, DC. Yes - in their world, green is a phase color!
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
It sounds like a large fusible link.
That's pretty much what it is
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Which open after the conductor has already faulted, hopefully preventing/reducing damage to the other conductors in the set. It may be better to limp along on a reduced number of parallel conductors than it is to lose the entire facility while waiting for new conductors.
Dsg319
Senior Member
- Location
- West Virginia
- Occupation
- Wv Master “lectrician”
Wonder what tool was used on those crimp lugs?
Choice_Gorilla
Senior Member
- Location
- New England
- Occupation
- Journeyman Electrician
The paperwork says they don’t offer over current protection, just short circuit. Personally never even heard of the things, let alone installed them.
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
A poor moron was used.
Which is the "dict def" of a tool.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I believe that the ConEd spec calls for an indenter type of crimp.
AlbertL57
Member
- Location
- Falls Church, VA
- Occupation
- Solar maintainer
I believe a lot of their use is on the utility side, specifically on secondary networks (multiple transformers paralleled on the LV side, usually underground) where available fault currents are very high. By quickly isolating individual faulted cables, the limiters help maintain service continuity.
David Castor
Senior Member
- Location
- Washington, USA
- Occupation
- Electrical Engineer
Bussman makes them. Not sure why the long lead time. It's essentially a current-limiting fuse. Here's a TCC for 500 kcmil Buss limiter (according to EasyPower).
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I don't think you can use them since they would be in parallel
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
How does thus compare to a typical OCPD? Your example is for a limiter to protect 500kcmil which is typically applied at roughly 380A. The TCC shows this limiter would carry roughly 2500A for10 sec before opening. This doesn't seem like it would be easy to coordinate with.