[PennKent]

While making up the power cord for a hydraulic motor (110V / 2.5kW), I noticed the internal motor leads are only 14 AWG. Seems undersized, given the load. I was planning to use 10 AWG SO cord, but now I'm not sure if that's overkill. I'm also not sure if the motor is incorrect for this application (car lift), even though it is a factory off-the-shelf hydraulic motor/pump/valve set-up. Motor is started with a simple push-button and relay contactor.

The receptacle is a NEMA L5 that is fed with 10 AWG from a 30A breaker.

Any explanation and/or advice (especially about why the internal motor wiring seems undersized) would be most appreciated.

 

[chandler48]

You are correct in using the #10 wiring. The internal wiring is specified by the manufacturer and installed as they determine to be correct, based on the amperage rating, and all the name tag nomenclature. 30 amp breaker is appropriate.

Is the motor, by chance, a dual voltage motor. Can you set it up to run on 240 volts? Less amperage, smaller wire needed, and smaller ocp, although it would be a double breaker.

 

[surferdude2]

It's because the motor wires are wound together around a laminated core and that increases the impedance that they present to the source supply.

Impedance is determined by a combination of frequency, capacitance, inductance and resistance.

Your supply wire must comply with what current is allowed to flow through them without regard to anything but their resistance and insulation temperature rating.

 

[PennKent]

Thanks, chandler48, I appreciate the follow up. I sure wish it was a dual voltage motor because that is exactly what I would do. In fact, the dedicated circuit that I had installed was mistakenly put in as 240 with double breaker, so I would be all set!

 

[J. V.]

Motor leads incorporate a different insulation class than what we normally see.
Its rated for temperature, voltage and current. The insulation temp is rated much higher than building wire. This is why you see the difference on your end verses the manufacturers end.

This does not give green light to lower wire size on our end. We size to current and that is what you must size for regardless the size of the motor leads.