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EMT Type Conduit for Med Voltage Feeders

EMT Type Conduit for Med Voltage Feeders

EMT Type Conduit for Med Voltage Feeders

(OP)
Is EMT type coduit UL approved for use as a raceway means for med voltage (13.8 kV) feeders?

Joseph D. Legge, PE

RE: EMT Type Conduit for Med Voltage Feeders


Look like maybe it can.  Sure wouldn’t want to ever rely on it for served-equipment grounding.
 

RE: EMT Type Conduit for Med Voltage Feeders

I don't know about UL, but NEC Article 358 does not appear to prohibit it.  I don't think I've ever seen it used for 15 kv circuits however.  

RE: EMT Type Conduit for Med Voltage Feeders

Make sure there are no local restrictions.
  

RE: EMT Type Conduit for Med Voltage Feeders

Also, be careful about calling EMT "conduit."  It is a raceway, but it is "tubing."  
  

RE: EMT Type Conduit for Med Voltage Feeders

Based on my interpretation, the Canadian Electrical Code would prohibit using EMT for this application:

Section 36, High-Voltage Installations (>750 V)
36-100(2) Except as permitted in Paragraphs 1(b), 1(c), and 1(d), conductors used indoors or attached to buildings outdoors shall be:
(a) Installed in metal conduit; or
(b) Metal enclosed busways; or
(c) Cables having a continuous metal sheath, steel wire armour, or of the interlocking armour type; or
(d) Type TC tray cable installed in cable tray in accordance with Rule 12-2204.

As busbar says, EMT is tubing, not conduit.

RE: EMT Type Conduit for Med Voltage Feeders

Just to back up the above, the Canadian Electrical Code definition of "conduit" is:

"Conduit means a raceway of circular cross-section, other than electrical metallic tubing and electrical nonmetallic tubing, into which it is intended that conductors be drawn."

RE: EMT Type Conduit for Med Voltage Feeders

(OP)
Thanks very much for all of the good responses.  

I had a chance to review the NEC on this item last night.  What I found was:
NEC (1996) 710-4 Did NOT allow EMT to be used for this application.
NEC (1999) 300-37 Allows EMT to be used for this application.

It appears from 1996 to the 1999 code the writers had a change in heart about this issue.  

Joseph D. Legge, PE

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