rewiring a 110V compressor to 220V

[twowheeled]

Hi All, I need some pointers. I had an electrician install a dryer plug on a 30amp circuit into my garage which I believe is the NEMA 14-30P style outlet.

Sometime later I purchased a dual voltage compressor which is factory wired for 110V. Now I purchased the 4 prong cable and I'm having trouble rewiring the unit to run on 220V.

https://www.lowes.com/pd/Kobalt-KOBALT-30-Gallon-Two-Stage-Portable-Electric-Vertical-Air-Compressor/1000528965

Firstly I have opened up the motor access plate and followed the diagram to switch jumpers from the low to hi voltage configuration. I've tripled checked this.

There is no wiring diagram for the pressure switch. So following some google searching I've hooked up my 4 prong dryer cord as thus:
Red wire - Switch Line
Black wire - Switch Line
Ground - grounded to switch plate/compressor body
White neutral - Capped/not used.

When I turn the compressor on it does not run. I have tried switching the red/black lines and no effect. Measuring between the Red/black wire shows no voltage with multimeter. Measuring past the switch to the motor Line 1 and Line 2 terminals with switch ON shows current with my non contact pen.

Please any advice?

 

[yatg]

Check your receptacle to make sure you have 240V between X and Y.

 

[twowheeled]

Check your receptacle to make sure you have 240V between X and Y.

No, measuring with a multimeter shows no voltage between those. However the non contact tester beeps on them both.

 

[yatg]

Could be beeping because phantom voltage, or one leg is dead.
Make sure your meter is working by testing in a known live receptacle, 120v or 240v.

Check between X and G and Y and G to see if a leg is dead.

Check in the panel that the breaker is actually on.
Check the voltage on the breaker screws to rule out a bad breaker.

Turn off the breaker, pull out the receptacle, and check for correct wiring.

 

[twowheeled]

thank you, I am measuring 120V between Y/G and nothing at X/G assuming this is dead. Will be calling electrican back to fix the wiring.

 

[Duke74]

Yatg had a good answer. Did you meter across the breaker?

 

[Terry D]

Your non contact voltage detector will drive you crazy on something like this. Using a multimeter is your best choice. As said, measure voltage across breaker. If you dont have 240 volts across the two lugs, the problem is the breaker or the panel. Also check the power coming into the panel. Post a picture of the panel and breaker.

 

[wyliesdiesels]

Is it a 2 pole breaker? Whats the brand and model? Have a picture?

 

[u2slow]

The pressure switch wiring won't care if 120v or 240v. It just needs to be rated for the higher voltage. Switch opens/closes the circuit regardless of voltage.

 

[Norcal]

Non contact voltage testers are toys at best, they belong in the toy aisle at Walmart or Target.

 

[sparky 1971]

The tester leads may not be long enough to make contact in the receptacle. Pull the receptacle out and then check at the screw terminals.

I trimmed the plastic off mine to make them fit.

 

[Duke74]

Non contact voltage testers are toys at best, they belong in the toy aisle at Walmart or Target.

I agree with NorCal, I never use them. Always meter stuff.

 

[u2slow]

I use a non-contact voltage tester daily in my line of work.

You do have to understand the limitations and know when to verify with a multimeter.

 

[Terry D]

I use a non-contact voltage tester daily in my line of work.

You do have to understand the limitations and know when to verify with a multimeter.

I agree, They have there place.

 

[Norcal]

They do have their place, but a Wiggy and or a multimeter are more useful.

 

[Terry D]

They do have their place, but a Wiggy and or a multimeter are more useful.

I agree, when there is lugs, terminals, prongs, etc. A meter is the way to go. But one example, if you have a bunch of nm-b's in a basement and you want to find the one that is hot or the one that is dead, you cant beat a non-contact tester.

 

[Dagny]

The multimeter don't fit in the chest pocket of my carrharts.

 

[cannuck]

Most likely when the breaker was installed in the panel it was put on the wrong pair of terminals. to get 220 each leg has to be on a different side of the bus (that alternates all of the way down top to bottom 2 tabs L1 leg and 2 tabs L2 leg).

 

[Terry D]

Most likely when the breaker was installed in the panel it was put on the wrong pair of terminals. to get 220 each leg has to be on a different side of the bus (that alternates all of the way down top to bottom 2 tabs L1 leg and 2 tabs L2 leg).

That is possible on some panels, GE being one. If that was the case, you still would have 120 volts from each hot to ground/neutral, just not 240 volts from hot to hot. The OP claims he has 0 volts from one hot to ground. Most panels, no matter where you plug a 2-pole breaker in, you will get 240 volts

 

[Dagny]

FPE another

 

[u3b3rg33k]

Where I come from a non-contact tester is called a dumbstick. it can help you not be dumb. It can't tell you how dumb you're about to be, or how to do things smart, or if you're doing things smart.

If you need to do smart things, the dumbstick is the wrong tool. but it is a great tool to let you know you you're about to do something really dumb. or that someone else has done something dumb while you weren't looking.

 

[klassenl]

Where I come from a non-contact tester is called a dumbstick. it can help you not be dumb. It can't tell you how dumb you're about to be, or how to do things smart, or if you're doing things smart.

If you need to do smart things, the dumbstick is the wrong tool. but it is a great tool to let you know you you're about to do something really dumb. or that someone else has done something dumb while you weren't looking.

In my shop we call them death sticks.

 

[The Cobbler]

I have to ask, why are you putting a 15 amp 120v compressor onto a 30 amp 240v circuit? , also you didn't need 4 wire cable , 3 would be fine. 2 hots, 1 ground.

 

[Terry D]

The main thing about a non contact voltage tester is knowing when to use them and when not. And how to use one. They can be a very helpful tool when used correctly. I would not chance my life with one. But I bet most electricians own one

 

[Duke74]

Yes I own one but I have no idea where it is. Never used it so it’s lost among my stuff somewhere lol.

 

[wyliesdiesels]

Hi All, I need some pointers. I had an electrician install a dryer plug on a 30amp circuit into my garage which I believe is the NEMA 14-30P style outlet.

Sometime later I purchased a dual voltage compressor which is factory wired for 110V. Now I purchased the 4 prong cable and I'm having trouble rewiring the unit to run on 220V.

https://www.lowes.com/pd/Kobalt-KOBALT-30-Gallon-Two-Stage-Portable-Electric-Vertical-Air-Compressor/1000528965

Firstly I have opened up the motor access plate and followed the diagram to switch jumpers from the low to hi voltage configuration. I've tripled checked this.

There is no wiring diagram for the pressure switch. So following some google searching I've hooked up my 4 prong dryer cord as thus:
Red wire - Switch Line
Black wire - Switch Line
Ground - grounded to switch plate/compressor body
White neutral - Capped/not used.

When I turn the compressor on it does not run. I have tried switching the red/black lines and no effect. Measuring between the Red/black wire shows no voltage with multimeter. Measuring past the switch to the motor Line 1 and Line 2 terminals with switch ON shows current with my non contact pen.

Please any advice?

a couple of things that are incorrect here

compressor doesn't need a neutral so the 4 prong 14-30 dryer outlet is incorrect

you need a NEMA 6-30

and thus the 4-prong dryer cord is wrong as well.

 

[u3b3rg33k]

a couple of things that are incorrect here

compressor doesn't need a neutral so the 4 prong 14-30 dryer outlet is incorrect

you need a NEMA 6-30

and thus the 4-prong dryer cord is wrong as well.

14 series outlets aren't "wrong" they're just the most flexible. don't need the neutral? don't use it in your appliance.

 

[wyliesdiesels]

14 series outlets aren't "wrong" they're just the most flexible. don't need the neutral? don't use it in your appliance.

a 14 series outlet is 125/250v and is 4 prong. theyre wrong for a motor that is 240v. using one for a motor screams hack.

 

[Terry D]

You only need a cord with a 6-20p on it. I'm not a big fan of adaptors, but they do make one. You could change the receptacle to a 6-20r also, but if the 30 amp receptacle you have now is in a 2-gang box, that wouldn't be to easy to do.

Amazon.com

 

[u3b3rg33k]

a 14 series outlet is 125/250v and is 4 prong. theyre wrong for a motor that is 240v. using one for a motor screams hack.

disagree. it's exactly what dryers do. neutral is there for a lightbulb/timer. those could be 220v. why do outlets need to lack features? I'd rather have a neutral and an appliance that doesn't need one, than have a 6 series outlet and then have to re-install the wiring just to get a neutral.

it'd be like only installing only 1-15R outlets because you're not planning on using a 5-15P today.

if you hardwired it, sure. then it's strange. but the whole point of outlets is you can plug in something else.

what if your uncle bob comes into town with his RV and wants to plug in? sorry bob. no neutral. better run your generator all night!

 

[larry_g]

To the OP

You show wiring for the switch for proper 240v operation, good. Have you also rewired the MOTOR for 240v operation??

lg
no neat sig line

 

[Terry D]

Not to get off track here, but a RV 30 amp is 120 volt, its a TT-30r. The 240/120 volt RV is a 50 amp, 14-50r, same as a range receptacle. Neither one will plug into that 30 amp receptacle the OP has. He could plug a dryer into it. This is just my opinion, I feel that each piece of equipment should have its own receptacle to plug into, then you don't have to worry about not being able to use something when something else is plugged in

 

[Norcal]

disagree. it's exactly what dryers do. neutral is there for a lightbulb/timer. those could be 220v. why do outlets need to lack features? I'd rather have a neutral and an appliance that doesn't need one, than have a 6 series outlet and then have to re-install the wiring just to get a neutral.

it'd be like only installing only 1-15R outlets because you're not planning on using a 5-15P today.

if you hardwired it, sure. then it's strange. but the whole point of outlets is you can plug in something else.

what if your uncle bob comes into town with his RV and wants to plug in? sorry bob. no neutral. better run your generator all night!

It SCREAMS extreme ignorance to supply a neutral for a appliance that does not need it, the only appliances that do require is are clothes driers & ranges.

As to RV's, any self respecting RVer has a adapter from 30A to 15A, and 50A to 15A, if not they can run on battery power, the 50A 125/250V is a dual voltage device, a RV has no 240V loads only 120V.

 

[u3b3rg33k]

It SCREAMS extreme ignorance to supply a neutral for a appliance that does not need it, the only appliances that do require is are clothes driers & ranges.

As to RV's, any self respecting RVer has a adapter from 30A to 15A, and 50A to 15A, if not they can run on battery power, the 50A 125/250V is a dual voltage device, a RV has no 240V loads only 120V.

outlets are rarely for a specific appliance. you may put an air compressor there. the next owner may not be a car guy but put an EVSE there. or maybe he wants to plug in the RV. or a welding cart with a mini-sub panel so you can plug in lights and grinders. 14-30/50 are perfect for that. a few RACO boxes bolted to the side of a 2 pole square D box with 2 single pole 20A breakers in it. now I can run my grinders and lights and welder without running cords everywhere.

you know what RVers don't have? 12kVA transformers to make a neutral where one doesn't exist. I've not seen many RVs with enough battery to run an AC.

 

[pattenp]

It was asked and not answered; I'm curious too as to why the need to convert the compressor to 240V?

 

[wyliesdiesels]

disagree. it's exactly what dryers do. neutral is there for a lightbulb/timer. those could be 220v. why do outlets need to lack features? I'd rather have a neutral and an appliance that doesn't need one, than have a 6 series outlet and then have to re-install the wiring just to get a neutral.

it'd be like only installing only 1-15R outlets because you're not planning on using a 5-15P today.

if you hardwired it, sure. then it's strange. but the whole point of outlets is you can plug in something else.

what if your uncle bob comes into town with his RV and wants to plug in? sorry bob. no neutral. better run your generator all night!

Better go read the schematic for an electric dryer then

Every electric dryer ive owned had a 120v motor. Why? Because the manufacturers want to save money by using one motor for both electric and gas versions.

So while you think theres a 240v motor in that electric dryer, in actuality its most likely a 120v motor and the only thing thats 240v is the heating coil... opppsss

 

[u3b3rg33k]

either way. doesn't change my point about having a neutral available being a good thing.

what did @twowheeled 's electrician find?

 

[yatg]

In my dryer, 2002 vintage, the mechanical timer is also 240v.

 

[wyliesdiesels]

either way. doesn't change my point about having a neutral available being a good thing.

what did @twowheeled 's electrician find?

A neutral available for a motor that doesnt need it? Or for a possible future circuit that would require addl overload protection...

Makes perfect sense... [sarcasm]

 

[Showkey]

Wow………. it’s Christmas and the electricians are arguing*………..what a surprise ??????


*about nothing