Wiring a 100amp outlet/connection- typical practice?

[tarbellb]

Im in the middle of a service line upgrade for my property and shop.

I will need a few high amp connections in the shop for certain tools (large 20hp VFD screw compressor, laser machine, welders, etc..)

What is considered best practice or typical for a 100amp and 60amp 1ph 240v connection
_ hardwired?
_ do i need or want a shutoff
_ anything else to consider


My setup will be using surface mount conduit, the run from box to panel is under 10ft

 

[u2slow]

Pin/sleeve is often used for these higher amp connections. I would hardwire though, as those get really pricey.

At 10' I'm content to use the breaker as the disconnect.

 

[tarbellb]

The panel/load center is on exterior, if that makes a difference @u2slow

 

[wyliesdiesels]

At 10' I'm content to use the breaker as the disconnect.

only allowed if the equipment is within site of the disconnect, which in the OP's case, is not

 

[wyliesdiesels]

compressor and I assume laser machine, are not portable, so i would hardwire those to a disco.

the welders, I assume, are portable and thus a plug and receptacle would be best

what is the make and model on the welder?

 

[wyliesdiesels]

The panel/load center is on exterior, if that makes a difference @u2slow

it does. see above comment #4

 

[u2slow]

only allowed if the equipment is within site of the disconnect, which in the OP's case, is not

I assumed it was within sight, since 10'.

OP has now clarified.

 

[matt_i]

Hardwired is cheapest but gives minimum flexibility in the layout as times change. 3 pole non-fused disconnects are still pretty cheap, in good-used condition, if you want to go that route.

A screw compressor or machine tool (etc) may have its own 3 pole disconnect native to the machine...

 

[mike93lx]

If all the equipment will be line of sight to a spot in the shop, a sub panel would likely be easiest.

How are you hooking up the 20hp vfd? That's not single phase, right?

 

[tarbellb]

If all the equipment will be line of sight to a spot in the shop, a sub panel would likely be easiest.

How are you hooking up the 20hp vfd? That's not single phase, right?

Yes it's a single phase compressor

Sub panel could be the move. I'm pulling 100amp feeder to the original sub panel. My thought was running a couple surface mount boxes would be easier but now a the shut offs requires it could be cheaper.

 

[mike93lx]

Yes it's a single phase compressor

Sub panel could be the move. I'm pulling 100amp feeder to the original sub panel. My thought was running a couple surface mount boxes would be easier but now a the shut offs requires it could be cheaper.

20hp on single phase service? Is this OK with your poco?

 

[alfredeneuman]

Any switching device between the VFD and the motor will, when under load, will do damage to the VFD's output transistors. This will greatly decrease the life of the VFD.
Make sure the equipment isn't running when you throw the switch (except in an emergency)

 

[Lassen Forge]

20hp on single phase service? Is this OK with your poco?

Had to look it up - 1ø 230 V, a 20 HP motor pulls 88 amps. If you got the service and the $$ for electricity, why not? Cheaper in the long run to go 3ø...

 

[mike93lx]

Had to look it up - 1ø 230 V, a 20 HP motor pulls 88 amps. If you got the service and the $$ for electricity, why not? Cheaper in the long run to go 3ø...

Because power companies will have limits as motors draw far more current at startup than running.

A normal residential transformer will not support a 20hp motor starting as it could be a few hundred amps

Limits are usually 5, 7.5 or 10hp on the high end for residential service