Machine Tool Wire

[ECTech]

I could not find Machine Tool Wire insulation wire in the Annex C tables for number of conductors in conduit. My question is can you run MTW in a conduit?

 

[ike5547]

I could not find Machine Tool Wire insulation wire in the Annex C tables for number of conductors in conduit. My question is can you run MTW in a conduit?

If you look at a roll of THHN you will probably notice the following designations:

THHN or THWN or MTW

Use the THHN column for pipe fill.

 

[ECTech]

Ok thank you for your help.

 

[winnie]

However if the particular spool of wire that you are using only says 'MTW', then you cannot use it for NEC compliant wiring.

-Jon

 

[jumper]

However if the particular spool of wire that you are using only says 'MTW', then you cannot use it for NEC compliant wiring.

-Jon

I looked in T310.13 and that was what I was thinking.I did a quick search and did not find anything specific. What makes it a violation? T310.13 location column?

 

[winnie]

IMHO table 310.13 tells us where a particular type of wiring can be used, and lists MTW for wiring per NFPA 79 and in Machine tools per article 670.

On the other hand, the text of 310.13 (2002) says 'These conductors shall be permitted for use in any of the wiring methods recognized in Chapter 3......', and if you look at the entry for SIS wiring it says 'switchboard wiring only', but the entry for MTW doesn't say 'Machine tool wiring _only_'. So perhaps it is allowed.

One caution: in my experience, wire that says 'MTW' only is more finely stranded than wire that is rated THxx/MTW; this may cause problems with respect to the ratings of terminals.

-Jon

 

[petersonra]

IMHO table 310.13 tells us where a particular type of wiring can be used, and lists MTW for wiring per NFPA 79 and in Machine tools per article 670.

On the other hand, the text of 310.13 (2002) says 'These conductors shall be permitted for use in any of the wiring methods recognized in Chapter 3......', and if you look at the entry for SIS wiring it says 'switchboard wiring only', but the entry for MTW doesn't say 'Machine tool wiring _only_'. So perhaps it is allowed.

One caution: in my experience, wire that says 'MTW' only is more finely stranded than wire that is rated THxx/MTW; this may cause problems with respect to the ratings of terminals.

-Jon

MTW insulation is often thicker as well, and harder to pull.

 

[TOOL_5150]

MTW seems to be very "sticky" not in the litteral sence, but I was trying to pull out 3 #8's [solid] out of a 3/4 pipe and they almost didnt budge. The pipe was less than 20'

~Matt