Load center wiring in a large machine

Tiberinus

New User
Location
Naugatuck, Ct
Occupation
Engineer
Hello everyone,

Our large machine requires internal wiring for lights and receptacles (Nema 5-15, L6-20, L15-20) connected to an internal 3-phase load center. This machine is wired for European standards at 400V/230V 3-phase, and we need to convert it to the US market.

I'm considering using THHN (tray cable wiring) since NM-B doesn't have the necessary temperature rating or flexibility. However, I've noticed that THHN doesn't adhere to the NEC color code for connecting to the load center (specifically a Schneider QO320L125S0 3-phase 125Amp).

My questions are:

  1. Will there be any issues with using wires that don't comply with the NEC color code when connecting to the load center?
  2. If so, will I need to remark each wire?
For reference, the THHN cable includes a green ground wire.

BTW I'm not an electrician.

Thanks in advance for your assistance!
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
One big hurdle you may encounter is the requirement that many jurisdictions have that any prewired machine bear a NRTL (UL) label,
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
There is no nec color code other than for ground and grounded conductors.

You can re-identify single conductors color wise as long as they are larger than #6.

Thhn is not tray cable. It is a single conductor wire.

NM is not appropriate for machine wiring.
 

cashpoppper

Member
Location
usa
Occupation
hvac
UL approval might be the largest concern. hi-POT test and everything with certified equipment, maybe that's CA? I forget now.. good luck.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I would look closely at whether the load center is suitable. If it is, maybe you don't need to do anything to rewire the receptacles and lights. There is some dispensation for the color coding if the wires inside a cable. However, most European wiring is not UL listed.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Uh... side issue: what voltage are you rewiring this for? 208Y120 or 240/120 3ph 4 wire delta? Because that Square D panel is 240V max, so if you are redoing this for the US market to be 480/277V in lieu of 400/230V, that panel isn't going to fly (unless you are also adding a transformer to feed that part). Also, that Square D part number, with the "SO" suffix, means "Special Order" and appears to be something for South America, so it might not be UL listed.
 
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