Need garage electrical advice

[chumpy36]

I'm doing a garage apartment above my current garage. We needed to run a subpanel there and so I'm taking advantage of the extra HP provided by new service to the apartment and installing a car charger outlet and a 220 outlet for a compressor and possibly other goodies like a welder down the road.
My compressor is a 4b236b Speedaire 60 gallon that someone gave me for free. The motor needs to be replaced but otherwise it's in decent shape except for some rust I needed to take care of on the mounting feet. So here are the variables that I need to cover with an outlet.
Compressor is 240v, 15 amp, single phase according to the sticker. I would like to in the future, use a welder or other high amp device. So I would like the outlet to be at least 30 amps and have a common plug specification.
The electrician (without asking me, has put in "a 2 pole 20 amp twist lock cord 3 prong for your compressor". See pic. Am i right in saying this would work well for the compressor but not for higher amp stuff like a welder? And how to fix knowing I want the higher amperage and a common cord between the compressor and the welder?
Thanks much!

 

[The Cobbler]

put in "a 2 pole 20 amp twist lock cord 3 prong for your compressor

those plugs are probably not Horse power rated past 3 hp , so ....

 

[cannuck]

depends upon how much welder you anticipate. Most 180A and up machines default to a 50A plug. If you were going to stick with a "body shop" inverter machine - say up to a Miller 211 size - than your 20A twist lock will most likely carry the load. I usually wire twist lock sockets to 30A - but that just because the equipment I used to build and operate used that as a single phase outlet standard.

 

[PCustoms]

I'm doing a garage apartment above my current garage. We needed to run a subpanel there and so I'm taking advantage of the extra HP provided by new service to the apartment and installing a car charger outlet and a 220 outlet for a compressor and possibly other goodies like a welder down the road.
My compressor is a 4b236b Speedaire 60 gallon that someone gave me for free. The motor needs to be replaced but otherwise it's in decent shape except for some rust I needed to take care of on the mounting feet. So here are the variables that I need to cover with an outlet.
Compressor is 240v, 15 amp, single phase according to the sticker. I would like to in the future, use a welder or other high amp device. So I would like the outlet to be at least 30 amps and have a common plug specification.
The electrician (without asking me, has put in "a 2 pole 20 amp twist lock cord 3 prong for your compressor". See pic. Am i right in saying this would work well for the compressor but not for higher amp stuff like a welder? And how to fix knowing I want the higher amperage and a common cord between the compressor and the welder?
Thanks much!

Knowing that there's a ton of new colors for nm-b, I'd still be concerned that that wire is only 14awg...

What size is the breaker?


Any writing on the wire jacket?

 

[chumpy36]

Knowing that there's a ton of new colors for nm-b, I'd still be concerned that that wire is only 14awg...

What size is the breaker?


Any writing on the wire jacket?

I don't know the breaker but I can find out when electrician comes next. In any case, you're saying the wire run there needs to be bigger?

 

[wyliesdiesels]

gallon capacity means absolutely nothing when it comes to sizing circuits for motors.

what is the HP rating on the motor nameplate? Im guessing 3hp

you would need a 3HP rated receptacle for it, but those are typically nema 6-50 and the compressor calls for a 15a 240v circuit. a nema 6-15 or 6-20 isnt gonna be rated for more than about 2hp

the receptacle the welder will need can vary wildly depending on model

 

[wyliesdiesels]

Knowing that there's a ton of new colors for nm-b, I'd still be concerned that that wire is only 14awg...

What size is the breaker?


Any writing on the wire jacket?

not all brands of NM-b are color coded. totally depends on manufacturer.

 

[wyliesdiesels]

I don't know the breaker but I can find out when electrician comes next. In any case, you're saying the wire run there needs to be bigger?

please look at the embossed writing on the jacket of the white NM-b. does it say 14/2 or 12/2?

 

[PCustoms]

not all brands of NM-b are color coded. totally depends on manufacturer.

Obviously, I was saying the same thing, but that white NM-B looks undersized to me (and typically represents 14awg wire).

 

[BrandonV]

The rating on those motors is usually going to hover around 3.7 HP at 15.7A. A 20A receptacle seems satisfactory for the compressor side of the equation. IIRC you're not going to find a receptacle rated above 3HP (that being a 6-50). Code is a different story with the FLA value.

Someone else who knows the NEC can probably chime in, but as long as you are not using the cord and plug as the disconnecting means I believe you do not have to get a HP rated receptacle which is called out in 430.109(F).

 

[chumpy36]

those plugs are probably not Horse power rated past 3 hp , so ....

The motor is 3hp.

 

[chumpy36]

depends upon how much welder you anticipate. Most 180A and up machines default to a 50A plug. If you were going to stick with a "body shop" inverter machine - say up to a Miller 211 size - than your 20A twist lock will most likely carry the load. I usually wire twist lock sockets to 30A - but that just because the equipment I used to build and operate used that as a single phase outlet standard.

I won't need much. Really just small fab jobs and fixing bits here and there.

 

[chumpy36]

please look at the embossed writing on the jacket of the white NM-b. does it say 14/2 or 12/2?

It says 14awg so should this be upsized? If I use a small welder like mentioned above and the compressor, it looks like that plug will work? I just need the wiring upgraded?

 

[BrandonV]

Out of curiosity what does it say on the front of that receptacle? That almost looks like a L5...

 

[wyliesdiesels]

It says 14awg so should this be upsized? If I use a small welder like mentioned above and the compressor, it looks like that plug will work? I just need the wiring upgraded?

the electrician is an idiot. should be fired after he puts in the correct circuit at his cost unless you didnt show him the compressor in question. either way he put the wrong breaker in.

14/2 should not be on a 20a breaker. nor should a 15 single receptacle (if that is what he put in).

3HP motor needs 21.25a rated wire.

14/2 NM-b isnt gonna cut it here. nor is a 15a receptacle (if that is what he put in)

as far as the welder goes, it really depends on the model. some come with 6-50p on the cord...

 

[gregjsmith]

You’re correct—the 20A twist-lock outlet your electrician installed will work fine for the compressor since it’s rated for 240V and 15A, but it won’t cut it for higher-amp devices like a welder. Most welders require at least a 30A or even 50A circuit, depending on the model and power requirements.

If you want a single outlet that can handle your compressor and future higher-amp equipment, you should consider upgrading the circuit to a 30A or 50A breaker and installing a more common outlet type, like a NEMA 14-30 or 14-50. These outlets are versatile, widely used, and can accommodate a range of devices with the correct plugs.

Keep in mind that your compressor’s current plug won’t fit into a higher-amp outlet, so you’ll need to either change the compressor’s plug to match the new outlet (only if it’s safe to do so for the compressor’s wiring and motor specs) or use an adapter cord that converts the 20A plug to the new outlet type. Talk to your electrician about the upgrade before the walls are closed up! Planning for the higher amp devices now will save you much trouble later.

 

[mike93lx]

You’re correct—the 20A twist-lock outlet your electrician installed will work fine for the compressor since it’s rated for 240V and 15A, but it won’t cut it for higher-amp devices like a welder. Most welders require at least a 30A or even 50A circuit, depending on the model and power requirements.

If you want a single outlet that can handle your compressor and future higher-amp equipment, you should consider upgrading the circuit to a 30A or 50A breaker and installing a more common outlet type, like a NEMA 14-30 or 14-50. These outlets are versatile, widely used, and can accommodate a range of devices with the correct plugs.

Keep in mind that your compressor’s current plug won’t fit into a higher-amp outlet, so you’ll need to either change the compressor’s plug to match the new outlet (only if it’s safe to do so for the compressor’s wiring and motor specs) or use an adapter cord that converts the 20A plug to the new outlet type. Talk to your electrician about the upgrade before the walls are closed up! Planning for the higher amp devices now will save you much trouble later.

Depending on the duty cycle, 14 can supply a 6-50 for a welder within Code. It's on the bottom end and smaller than I would run, but you do not need a 50a rated wire for a welder by default.

Code Q&A

Q. How do I size the conductors for an arc welder?

www.ecmweb.com

 

[wyliesdiesels]

You’re correct—the 20A twist-lock outlet your electrician installed will work fine for the compressor since it’s rated for 240V and 15A, but it won’t cut it for higher-amp devices like a welder. Most welders require at least a 30A or even 50A circuit, depending on the model and power requirements.

If you want a single outlet that can handle your compressor and future higher-amp equipment, you should consider upgrading the circuit to a 30A or 50A breaker and installing a more common outlet type, like a NEMA 14-30 or 14-50. These outlets are versatile, widely used, and can accommodate a range of devices with the correct plugs.

Keep in mind that your compressor’s current plug won’t fit into a higher-amp outlet, so you’ll need to either change the compressor’s plug to match the new outlet (only if it’s safe to do so for the compressor’s wiring and motor specs) or use an adapter cord that converts the 20A plug to the new outlet type. Talk to your electrician about the upgrade before the walls are closed up! Planning for the higher amp devices now will save you much trouble later.

incorrect since the motor is 3HP with a 16a FLA. The sticker he is basing that off of is wrong.

 

[chumpy36]

You’re correct—the 20A twist-lock outlet your electrician installed will work fine for the compressor since it’s rated for 240V and 15A, but it won’t cut it for higher-amp devices like a welder. Most welders require at least a 30A or even 50A circuit, depending on the model and power requirements.

If you want a single outlet that can handle your compressor and future higher-amp equipment, you should consider upgrading the circuit to a 30A or 50A breaker and installing a more common outlet type, like a NEMA 14-30 or 14-50. These outlets are versatile, widely used, and can accommodate a range of devices with the correct plugs.

Keep in mind that your compressor’s current plug won’t fit into a higher-amp outlet, so you’ll need to either change the compressor’s plug to match the new outlet (only if it’s safe to do so for the compressor’s wiring and motor specs) or use an adapter cord that converts the 20A plug to the new outlet type. Talk to your electrician about the upgrade before the walls are closed up! Planning for the higher amp devices now will save you much trouble later.

Thanks for this. Currently there is no plug on the compressor. The wiring was removed before I got it so it will need a cord. So if I understand you correctly I should ask the electrician to upgrade the circuit to 30 or 50 amps (Probably 30 as I will only want a small welder I think) and then have him put in a nema 14-30 and then get a nema 14-30 cord for the compressor?

 

[mike93lx]

Thanks for this. Currently there is no plug on the compressor. The wiring was removed before I got it so it will need a cord. So if I understand you correctly I should ask the electrician to upgrade the circuit to 30 or 50 amps (Probably 30 as I will only want a small welder I think) and then have him put in a nema 14-30 and then get a nema 14-30 cord for the compressor?

There is no need for a neutral or a 4 wire plug. 3 wire is fine for a compressor and welder.

Depending on your welder, you.may need a 50a breaker, which makes the circuit no compliant for use with anything but a welder unless you run either 6/2 nm-b or #8 thhn in conduit

 

[chumpy36]

So I need a 3 wire power cord for the compressor and a 3 wire nema 14-30 outlet? And a 30 amp breaker? and upgraded wiring?

 

[chumpy36]

There is no need for a neutral or a 4 wire plug. 3 wire is fine for a compressor and welder.

Depending on your welder, you.may need a 50a breaker, which makes the circuit no compliant for use with anything but a welder unless you run either 6/2 nm-b or #8 thhn in conduit

I'm more interested in a smaller welder and not a massive one. So most of those use a 3 prong power cord.
so I would need 30 amp breaker and a three prong 220 outlet (is that 14-300 nema?) and a three prong 220 power cord for the compressor?

 

[sparky 1971]

I'm more interested in a smaller welder and not a massive one. So most of those use a 3 prong power cord.
so I would need 30 amp breaker and a three prong 220 outlet (is that 14-300 nema?) and a three prong 220 power cord for the compressor?

A 240 volt welder receptacle is a 6-50R. There are exceptions to the rule but not in this case.

 

[mike93lx]

I'm more interested in a smaller welder and not a massive one. So most of those use a 3 prong power cord.
so I would need 30 amp breaker and a three prong 220 outlet (is that 14-300 nema?) and a three prong 220 power cord for the compressor?

For a welder, I would run 10/2 (two conductors plus a ground), a 6-50 receptacle and a 50a breaker. Label it "for welder use only".

For the compressor, I would run 10/2 to an a/c disconnect and a 30a breaker. Then hard wire the compressor with a whip. This would support a real 3hp and if you aren't sharing the circuit, there is no need to be able to unplug a 60 gallon compressor

If you really want only one circuit for both, it would be 10/2, a 6-50 receptacle and a 30a breaker. If you end up with a welder that won't run on a 30a breaker, add a second circuit at that point. Just don't unplug the compressor while it is running

 

[Norcal]

That receptacle is a 125V rated locking device, it's only a Twistlock® if a Hubbell product, but newer locking receptacles are color coded, yellow.= 125V, blue is 250V.

 

[BrandonV]

That receptacle is a 125V rated locking device, it's only a Twistlock® if a Hubbell product, but newer locking receptacles are color coded, yellow.= 125V, blue is 250V.

Yup. It looks like to me a Leviton L5-20R which makes the 14 gauge NM-B even more interesting.

 

[chumpy36]

For a welder, I would run 10/2 (two conductors plus a ground), a 6-50 receptacle and a 50a breaker. Label it "for welder use only".

For the compressor, I would run 10/2 to an a/c disconnect and a 30a breaker. Then hard wire the compressor with a whip. This would support a real 3hp and if you aren't sharing the circuit, there is no need to be able to unplug a 60 gallon compressor

If you really want only one circuit for both, it would be 10/2, a 6-50 receptacle and a 30a breaker. If you end up with a welder that won't run on a 30a breaker, add a second circuit at that point. Just don't unplug the compressor while it is running

Thanks for this. So, it looks like the electricians ran wire and a receptacle only suitable for the compressor itself and nothing else. So if I understand you right, I could have him run 10/2 wire, a 6-50 receptacle and a 30 amp breaker (might be 30 amp breaker already but not sure). Then, I could wire the compressor with a 6-50 power cord which I could plug in and later when I get a welder, I could use it in the same receptacle? The welder I'm looking at, the spec have a recommendation for a 30 amp breaker. So for now that seems sufficient but if I needed more I would just swap out the 30 amp for a 50?
Thanks for the reply

 

[wyliesdiesels]

Thanks for this. So, it looks like the electricians ran wire and a receptacle only suitable for the compressor itself and nothing else.

That receptacle isnt even suitable for the compressor not to mention several major issues with it.

electrician should be fired.

 

[chumpy36]

That receptacle isnt even suitable for the compressor not to mention several major issues with it.

electrician should be fired.

Can you explain the issues so I can take it to the contractor?

 

[mike93lx]

Thanks for this. So, it looks like the electricians ran wire and a receptacle only suitable for the compressor itself and nothing else. So if I understand you right, I could have him run 10/2 wire, a 6-50 receptacle and a 30 amp breaker (might be 30 amp breaker already but not sure). Then, I could wire the compressor with a 6-50 power cord which I could plug in and later when I get a welder, I could use it in the same receptacle? The welder I'm looking at, the spec have a recommendation for a 30 amp breaker. So for now that seems sufficient but if I needed more I would just swap out the 30 amp for a 50?
Thanks for the reply

If you use a 50a breaker on #10 wire, it is no longer suitable for anything but a welder.

I dont think I would have that electrician do any more work

 

[chumpy36]

If you use a 50a breaker on #10 wire, it is no longer suitable for anything but a welder.

I dont think I would have that electrician do any more work

Do you mind explaining why it's not suitable for anything but a welder?
I am asking that the electrician not be working here once I understand what it was that he did that was so offsides.

 

[mike93lx]

Do you mind explaining why it's not suitable for anything but a welder?
I am asking that the electrician not be working here once I understand what it was that he did that was so offsides.

Welder-only circuits have some special rules that allow them to use wire rated for lower ampacity than normal because they are intermittent use as a function of their duty cycle. So #10 nm-b is normally only good for up to 30a but it can be used on a 50a welder circuit assuming that the welder meets the duty cycle restriction. I'd have to check the table, but I think it might be around 50%.

 

[chumpy36]

Got it. That makes sense. Appreciate it.

 

[wyliesdiesels]

Can you explain the issues so I can take it to the contractor?

well first off he used 14/2 NM-b on a 20a breaker.

also if that receptacle is an L5-20, its not 240v so your compressor wouldnt even work. not to mention the circuit is too small for a 3HP motor

 

[BrandonV]

well first off he used 14/2 NM-b on a 20a breaker.

also if that receptacle is an L5-20, its not 240v so your compressor wouldnt even work. not to mention the circuit is too small for a 3HP motor

Yup. The first one is bad enough to just pull the plug (no pun intended) immediately on whoever is doing this.

There is also the possibility they just hooked up 240V to the 120V NEMA plug. Seen contractors do that a bunch. One reason I like to test everything before plugging in loads.

 

[chumpy36]

so I need 10/2 wire, a nema 6-50 receptacle and at least a 30 amp breaker yes? And he put none of this in?

 

[chumpy36]

you guys were right, it's a leviton, L5-20 120v and yellow. So he's put in the wrong receptacle, the wrong wire and maybe the wrong breaker?

 

[wyliesdiesels]

yes its all wrong. you cant put a 20a receptacle on 15a rated wire (14/2) on a 20a breaker. further, the circuit is too small for the compressor.

 

[sparky 1971]

yes its all wrong. you cant put a 20a receptacle on 15a rated wire (14/2). and you cant put 15a rated wire (14/2) on a 20a breaker. further, the circuit is too small for the compressor.

And to add: it's supposed to be a 240 volt circuit, is there a 120 volt receptacle connected to a two pole breaker? My guess is yes since post #1 says two pole 20 amp twist lock. The 'electric guy prolly thought that L5 was one of them fancy twotwenny plugins.

 

[wyliesdiesels]

yup and i didnt even get to that. so much wrong here