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Changing compressor wiring

Gilmore

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Hello, I'm new here so thank you for letting me join. I was given an old 230v compressor that is currently wired for 220v. I have a dedicated 240v double pole 30-amp plug wired in my shop for welder and heater use. I’m wanting to know if I can change the compressor wire to the same plug type as the welder and heater? I would be using a 30 amp, 10 gauge plug wire in the same outlet configuration as shown to the compressor switch. Would I also need to change the motor to switch wire to 10 gauge? 20240102_094951.jpg20240102_095008.jpg20231226_141529.jpg20231216_141223.jpg
 
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Gilmore

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What cordage and plug is currently on the compressor? Yes you can use a matching 6-30P on the end of the existing cord or if new cord is required I would use 12 gauge, SOOW, or SJOW.
It's currently wired for 220v with 12 gauge wire
 

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Gilmore

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What cordage and plug is currently on the compressor? Yes you can use a matching 6-30P on the end of the existing cord or if new cord is required I would use 12 gauge, SOOW, or SJOW.
Won't 12 gauge be to small for a 30 amp plug? All my other plug wires are 10 gauge to match the 30 amp plug and 240v system.
 

u2slow

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Motors and welders are special cases where the breaker is usually oversized to the wire. Your compressor is thermally protected against overload, so the breaker isn't tasked with that.

I have made a few adapter cords to get between 6-20R, 14-30R, and 6-50R. I also have a single circuit with several 6-20R's around the shop for convenience.
 
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Gilmore

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Motors and welders are special cases where the breaker is usually oversized to the wire. Your compressor is thermally protected against overload, so the breaker isn't tasked with that.

I have made a few adapter cords to get between 6-20R, 14-30R, and 6-50R. I also have a single circuit with several 6-20R's around the shop for convenience.
I already have a 6-30p cord to hook up to it at the switch. The motor wires though are still 12 gauge. If I hook up the 6-30p 10 gauge will I need to also change the 2 wires to 10 gauge from the motor to the switch? I apologize if I'm asking too many questions. I'm newish to electric wiring.
 

u2slow

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Does your hobby welder with a 6-50p plug have #6 cord? I think not.... same difference.
 
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Gilmore

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Does your hobby welder with a 6-50p plug have #6 cord? I think not.... same difference.
My welder has an adapter plug that goes to the 6-30r or it can be plugged into a 230/115 volt adapter
 
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Zeke

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Yes it has a blade switch
So the blade switch is to kill power like if the compressor was hard wired. I don't see anything wrong with that but it must be wired into the line voltage (cord) with the same size wire. Hopefully it's a 2 pole switch. Your choice of 10 ga stranded would be my choice in SJO cord or SO.

2_1_1024x1024.jpg
 

u2slow

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My welder has an adapter plug that goes to the 6-30r or it can be plugged into a 230/115 volt adapter
And the cord's AWG wire size?

My Code book (CEC) allows the breaker to be set at 250% of the motor's FLA. 12A×250%=30A. #12 wire is already sufficient for the motor's 12A FLA.

Fwiw, a plug-in device is UL/CSA approved, and not intended to be modified. The best we can do is look to Code and/or experience for guidance on making good choices.
 
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Gilmore

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So the blade switch is to kill power like if the compressor was hard wired. I don't see anything wrong with that but it must be wired into the line voltage (cord) with the same size wire. Hopefully it's a 2 pole switch. Your choice of 10 ga stranded would be my choice in SJO cord or SO.

2_1_1024x1024.jpg
 
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Gilmore

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And the cord's AWG wire size?

My Code book (CEC) allows the breaker to be set at 250% of the motor's FLA. 12A×250%=30A. #12 wire is already sufficient for the motor's 12A FLA.

Fwiw, a plug-in device is UL/CSA approved, and not intended to be modified. The best we can do is look to Code and/or experience for guidance on making good choices.
Ok I think I see what you are saying. The welder wire size is #12AWG and the current wire size to the compressor is also #12AWG so if I'm understanding correctly, I can wire the existing wire to a 6-30p and be good to go?
 

wyliesdiesels

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And the cord's AWG wire size?

My Code book (CEC) allows the breaker to be set at 250% of the motor's FLA. 12A×250%=30A. #12 wire is already sufficient for the motor's 12A FLA.

Fwiw, a plug-in device is UL/CSA approved, and not intended to be modified. The best we can do is look to Code and/or experience for guidance on making good choices.
that is permitted in the NEC only if the motor is hardwired
 
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Gilmore

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that is permitted in the NEC only if the motor is hardwired
In this case it is NOT hardwired. So do I go back to my thinking that it should be wired with #10 AWG plug to switch? If that is the case then does it also need #10 AWG from motor to switch?
 

u2slow

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Many pressure switches on plug-in compressors have an on/off lever.... is this the "blade switch"?

that is permitted in the NEC only if the motor is hardwired

We can also go down the rabbit-hole of not being allowed to modify listed/approved equipment.
 

wyliesdiesels

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In this case it is NOT hardwired. So do I go back to my thinking that it should be wired with #10 AWG plug to switch? If that is the case then does it also need #10 AWG from motor to switch?
as said previously the motor has integral overload protection which also protects the wire. i would just use an adapter instead of hacking up the factory cord

also, when you say switch, are you referring to the pressure switch? if so, doesnt that have factory installed conductors?
 
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Gilmore

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Many pressure switches on plug-in compressors have an on/off lever.... is this the "blade switch"?



We can also go down the rabbit-hole of not being allowed to modify listed/approved equipm

240v

Odd welder outlet. Most welders use a 6-50
240v?
My welder does have an original 6-50 plug and has 2 different adapters. One for the current 6-30r and one for 230/115 volt adapter.
 

wyliesdiesels

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I'm referring to the on/off switch. Is that also called a pressure switch?
yeah pressure switch. i wouldnt call it a blade switch, which is something entirely different.

so the previous owner removed the factory wiring from the pressure switch to the motor? smh why do people do that ****
 
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Gilmore

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yeah pressure switch. i wouldnt call it a blade switch, which is something entirely different.

so the previous owner removed the factory wiring from the pressure switch to the motor? smh why do people do that ****
No, he removed and replaced the old wiring, not sure if it was factory, to the pressure switch. The original wiring is still there from the pressure switch to the motor.
 
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Gilmore

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is the cord and plug currently on the compressor, what it came with from the factory? if so, why bother hacking it up? just use an adapter
I've searched for an adapter but I've only found ones that say not to use with a power inlet of over 20 amps
 

u2slow

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I've searched for an adapter but I've only found ones that say not to use with a power inlet of over 20 amps
They will all say that in order to be listed/approved. I typically make my own adapters.

All your options have been fully hashed out in this thread now.
 

Sumboodie

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Yes I know. I was questioning your 240v single comment and how it related to the plug picture
Because you keep changing voltages. You've mentioned 220, 230, 240v, 115v, etc.

At this point... good luck!
 
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Gilmore

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Because you keep changing voltages. You've mentioned 220, 230, 240v, 115v, etc.

At this point... good luck!
Yes, I've been answering questions regarding all those. I haven't been changing voltages at all. If you read the first post you'll see I have a 240v dedicated plug. The compressor I was told was rewired for a 220v 20amp plug which I don't have.
I'm new here and just trying to get some help and knowledge and if other members are going to ask me questions of how I run a welder or heater then I'm going to answer them.
 
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