220v 16.8amp Receptacle Install
I just bought a shaper to add to my workshop and need to install a 220 outlet into my garage in order to use it.
Shaper Motor Specs are:
I would like the circuit to accept up to 16.8 amps because that is what my jointer requires.
So with that said what size breaker and gauge of wire would be sufficient for a 16.8 receptacle? Can I use 3 wire cable?
Plug for shaper is standard size plug with two horizontal pins and one ground.
Also just wanted to check that as long as the amps of a machine plugged into this outlet sit below the amperage of the installed receptacle it will be safe to use that machine off that receptacle? For example my mortiser is 2.55 amps.
I appreciate any help.
You need a 240v-20A circuit. This would typically be wired with 12/2 cable.
Use a 20A-250v 3-wire receptacle. This will accept a 20A-250v plug OR the 15A-250v plug your shaper has.
That would be a NEMA 6-20R, similar to a Leviton #5821:
If it were me, I'd do what is suggested above, 12/2, 20 amp two pole breaker, and 20 amp 250 volt receptacles. These receptacles come in duplex also, but they're harder to find, and likely cost more than twice as much as a single.
The only problem might be with the jointer. A 16.8 amp motor on 240 volts is 3 HP. A 20 amp breaker might not start a 3 HP motor. The shaper motor is 2 HP (maybe 1-1/2), a 20 amp breaker will start it just fine.
To answer your other question, any 240 volt load that's less than the circuit size will work perfectly. Even if it's less than 1 amp.
I had envisioned a high-capacity 30 amp/120V circuit in a project home, hoping to power multiple high-power audio amplifiers from the dedicated 30 amp circuit, and found out a 30 amp/120V circuit takes a very unique plug/receptacle, nothing like the one pictured above. IIRC, the plug was designed to be inserted into the receptacle and then twisted. It was such a harebrained idea that I abandoned the quest for a high-amp 120V circuit and will wire in multiple dedicated 20 amp circuits to the location instead.
If a 30 amp circuit were run, using #10 wire, it certainly would start the jointer motor every time.
Trouble is, you'd need to use 30 amp receptacles with a 30 amp circuit, not 20 amp ones. The best way to go here would be twist-lock. NEMA L6-30. They're just a shade bigger than the 20 amp straight-blade ones, but will still fit in a one-gang box. I'd use deep boxes with #10's. The 120 volt version of this receptacle is a NEMA L5-30. They are the same size, but the blade configurations are different. Both of these are pretty common in commercial/industrial buildings.
My recommendation would be to temporarily connect the jointer to a 20 amp breaker, and see if it will start reliably. A 3 HP motor will push a 20 amp breaker to the max, some breakers will hold, others will trip. Another option would be 2 circuits, a 30 amp for the jointer, and a 20 amp for everything else.
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