Want longer cord for Delta TS

[Doug Miller]

18A @ 220V = almost 4KW -- that's pretty inefficient for 3 HP.

Perhaps you should check the melting point of copper wire, then reevaluate the basis for your belief.

[Greg O]

I just grabbed my Grainger catalog and checked through the 3 HP motors. Amps draw ranged from 13-19 for 240 volt, single phase motors. I generally figure about 5 amps per HP on 220 volts. Greg

[Max]

"Greg O" wrote

The plate on my 3HP Jet planer says 15 amps. It's plugged into a 20 amp outlet. No problems.

Max

[Lew Hodgett]

You just made it by the skin of your chiny chin chin.

A thermal-magnetic c'bkr is rated at 80% of nameplate when installed in a panel board or load center.

Thus a 20A c'bkr connected to a #12AWG conductor will handle 16A on a continuous basis.

Above 16A, you begin to operate on the time/current portion of the c'bkr which is less than continuous duty.

BTW, just for reference, a 15A c'bkr connected to a #14AWG conductor will only handle 12A on a continuous basis.

Case you are curious, it's all defined in your handy dandy NEC, a copy of which should be on file at your local library.

Lew

[Doug Miller]

A home-shop table saw doesn't even come close to being a continuous load, defined by the NEC as "a load where the maximum current is expected to continue for 3 hours or more."

Again: "continuous" = maximum current for 3 hours or more. Definitely not in any home shop, and probably not in any production shop either.

Indeed it is. That same handy dandy NEC tells you that the 15A limit on 14AWG wire is the maximum permitted rating of the overcurrent device, *not* the maximum rating of the conductor. Table 310.16 specifies that the ampacity (maximum current) of 14AWG copper wire is 20 amps with 60 or 75 deg C insulation, 25 amps with 90 deg C insulation.

FWIW, the factory-supplied power cord on my JET 3HP table saw is 14-3 SJT (rated at 105 deg C).

[Max]

I still have a copy of the NEC from prior to retirement.

Max (retired Deputy Fire Chief)

[Bill in Detroit]

Try to stay current: the thread for the spelling-challenged was last week. ;-)

Bill