flexible wire for motors and starters 1

[kkgg]

When using large gauge wire (MTW or THHN) such as #1,2,3 awg for starters and motors it gets hard to do any bends in the enclosure or into the motor because the wire is so rigid at that size. Is there an approved wire that is more flexible such as welding cable? This is used on 3 phase 480 V systems motors. Thanks

 

[busbar]

Do the terminal boxes satisfy NEC 430-12?

In most cases, the conductors also come under NEC Article 310 for use in raceways or cable assemblies. Welding cable will likely not meet NEC Article 310, but type DLO with a dual UL/NEC RHW-2 rating might be an acceptable compromise. 4AWG DLO is 105 strand and 1/0AWG is 273 strand—typically with thermoset [FREP/CSPE] insulation.

One producer of many is

http://www.aiwc.com/catalogsection/sellspdfs/dlo4pg.pdf

 

[corrosivo]

kkgg

Be careful with the extra flexible cable as the inner bunches of strands in this type of cable can slide out of the mechanical or compression type of connectors resulting in a loose connection later; when the bends (as in a tight enclosure) in the cables are too short radius or too near to the connector itself. Vibration and heating/cooling cycles starts the process. In my experience, large size cables always must be brazed to the terminals to prevent a loose connection caused by this behaviour of this type of cable, disregard this tip if you already doing this, I hope this helps

 

[jraef]

Busbar is right on. The most common one I see used by panel builders is DLO cable, although that is usually too expensive for long motor leads. Another choice inside of panels is flexible busbar, aka "Flexi-bus" from Erico. It is even more expensive than DLO, but you can make sharp right angles and complex twists, which often allows for better use of space. You can also drill the ends to make connections so as to avoid the need for lugs.

"Venditori de oleum-vipera non vigere excordis populi"

 

[tbmtech]

DLO is the way to go. We build and wire our own panels and DLO cable is all we use. This cable has its own ampacity tables due to the stranding and the insulation thereby reducing the size of the gauge required when compared to other types of wire.

 

[mc5w]

You can also order building wire with finer than normal stranding such as 19 strand #2 AWG wire rather than 7 strand #2.

Why don't you just simply use a bigger cabinet? In some instances it actually pays to use a bigger conduit or cabinet than what National Electrical Code requires because you are saving on labor.

Mike Cole, mc5w@earthlink.net

 

[busbar]

 
Another more flexible cable for panel work is dual-rated NEC/UL type SIS/XHHW-2. Eight-AWG and larger is often 133-strand, with 259-strand for larger gauges [ASTM B-173 Class H stranding]. XHHW rating also allows it to be used in raceways and general building-wire applications.]