I have 15kV shielded CT rated cables installed in the utility tunnel. I need to splice them for a project I am wokring on. Can I make a splice without j-box or splice box for this? The facility electrician is insisting that they can do that. The only exception I can find is 300.50 for underground installation. Is he correct?
15kV Cable Tray rated cable splices
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iceworm
Curmudgeon still using printed IEEE Color Books
- Location
- North of the 65 parallel
- Occupation
- EE (Field - as little design as possible)
You said CT rated cable, but didn't say if it was in Cable Tray
Suggested reading:
300.1
300.15
392.56
Generally, above ground splices are in boxes. I have seen a few that were in cable tray.
Ask your electrician for the specs and installation instructions on the kit to be used. Often these have instruction on where they can be used.
Even if the splice is to be located J-Box the kit needs to be correct for the cable. Either way, you must verify the kit is "approved methods".
ice
Ice,
Thanks for the reply. You are correct. I didn't give you the whole facts when I asked you a question. Here is the existing condition and I have to tap this installation for a new work.
The existing 15kV cable comes into the utility tunnel from UG with an m/c armored cable. The armored cable transitioned (spliced) to 15kV CT rated open cables without a j-box after about 500' of run in the tunnel ( I guess they ran out of armored cable??). Can't verify how the gound conductor in the armored cable transitioned to individual open cables.
The support of cable is mixture of cable try, uni-strut support, and cable straps either on the wall or ceiling depend on the locations. Now, is this installation seems to meet NEC?
Thanks for the reply. You are correct. I didn't give you the whole facts when I asked you a question. Here is the existing condition and I have to tap this installation for a new work.
The existing 15kV cable comes into the utility tunnel from UG with an m/c armored cable. The armored cable transitioned (spliced) to 15kV CT rated open cables without a j-box after about 500' of run in the tunnel ( I guess they ran out of armored cable??). Can't verify how the gound conductor in the armored cable transitioned to individual open cables.
The support of cable is mixture of cable try, uni-strut support, and cable straps either on the wall or ceiling depend on the locations. Now, is this installation seems to meet NEC?
iceworm
Curmudgeon still using printed IEEE Color Books
- Location
- North of the 65 parallel
- Occupation
- EE (Field - as little design as possible)
300.37 lists the available above ground wiring methods.
Guessing the system is 13.8kV Y or 12,460V Y: My biggest concern is the ground/bonding. If there is no ground/bond following along with the single conductors that means any fault current has to be carried by the earth or, the copper tape shields.
If the system is impedance grounded and a ground fault trips within a few seconds, the shields could easily burn up. If the system is solidly ground, a ground fault will vaporize the shields - generally considered not good. I'd be really curious about how the grounding\bonding conductor is continued through the transition from MC to 3 - single conductors.
Now, you say the plan is to T-tap the existing cable using a splice kit? That sounds wrong on so many levels. Lucky for me, you are getting out of my area. Hv&Lv is pretty knowledgable on MV. Maybe he will chime in.
ice
You want cable tray rated splices..http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtlxTyLX&VEVuQEcuZgVs6EVs6E666666--
Look at page 2 of 9
Also look at 392.56 as stated earlier, also Article 328. There is a bunch of references there.
If you are planning on T splicing, good luck. I would go to some type of seperable connector system. like this: http://www-public.tnb.com/util/docs/k150t.pdf
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