A/B Switch for 220V Outlet?

[Tommy R]

Hey folks,

I've got a small issue in my garage. I've got a single 220V outlet located rather inconveniently behind my air compressor. That alone isn't an issue, but occasionally I run a welder off that same outlet and it's kind of a pain accessing it. FYI, my breaker won't support both 220V items running simultaneously so it's just one at a time, which isn't much of a concern for me.

A basic solution would be to simply have an electrican relocate the outlet or even build my own extension cord to move the outlet where it's more accessible. This would be easy, but what I'd really like is to have an A/B switch mounted to the wall instead. In theory, both the compressor and welder would be plugged in all the time, but I would select which one would be active with the switch.

I would've thought something like this would be common, but my searches have shown otherwise. Does anyone have thoughts on this? Is the current draw simply too high for such a device to exist (at a reasonable price)?

Any helpful input would be much appreciated!

Thanks,
Tommy

 

[dogdog]

maybe figure something out with 1x of a 3-way switch and two relays ?

 

[The FIB]

Sounds like a double pole double throw switch might be what your looking for.

 

[Pwrgeek]

Search for a manual transfer switch. You can wire it to do what you are wanting.


Sent from my iPhone using Tapatalk

 

[Fallon]

Why not just put 2 outlets on that circuit? It's easy enough to turn off your compressor before you fire up the welder. Worst case scenario both turn on at the same time & you pop the breaker.

 

[Norcal]

Unless you can find a deal on a double pole double throw switch it may be cheaper to just run another circuit or it may be about the same cost depending on length and size of the run.

 

[theoldwizard1]

It is called a DPDT switch. They are not cheap and I don't know if they are "horsepower" rated. Leviton 1288 - 30-Amp Double-Pole, Double Throw Toggle - Amazon $80

 

[theoldwizard1]

Why not just put 2 outlets on that circuit? It's easy enough to turn off your compressor before you fire up the welder. Worst case scenario both turn on at the same time & you pop the breaker.

Probably not "legal", but BY FAR the fastest and easiest solution !

 

[wyliesdiesels]

Whats the HP rating on the compressor?

 

[Cmreschke]

A relay with a single pole would work.

 

[Cmreschke]

What's the circuit ampacity?

 

[Git]

I have two outlets on the same circuit and they are less than a foot apart.

It's a convenience thing. I would never run both machines at the same time. Both machines have their own on/off switch. Both machines have different plugs. At the time I opted to have two outlets instead of cutting off a factory plug and installing another one that was the same

 

[LS6 Tommy]

The device the OP is looking for is called an Double Throw Safety Switch. It allows you to select "A", "Off" or "B". I think they usually don't go below a 30A rating. They aren't cheap, either. Plan on spending around $300.00 just for the switch...

Tommy

 

[dpljmurphy]

Why not just put 2 outlets on that circuit? It's easy enough to turn off your compressor before you fire up the welder. Worst case scenario both turn on at the same time & you pop the breaker.

Not code, but neither should draw any vampire amperage, if i was comfortable with the wire gauge and receptacles; I'd plug them both in and only use one at a time.

If you sell the property; remove the second outlet to eliminate any liability.

 

[sberry]

If its practical nothing beats running a new wire, even if its not practical it may be the best and easiest. A bit of work is more reliable than buying some obscure part no one will appreciate and booger a good circuit.

 

[PT Doc]

You can add another outlet and in between them add an in,one motor rated switch, would give you some added protection but still not fool proof. Many have done the 2 outlets on one circuit and they just know how to use their own garage. Just do everyone a favor and when you move just leave one ouster on that circuit with an appropriate plug or just cap off the wires.

 

[CNGsaves]

Here's the solution:
. . . . "harvest/remove" that 240v outlet and instead hard wire compressor
properly & dedicate that circuit for the air compressor

. . . . install new circuit with appropriate wiring and breaker for the welder
and re-use that 240v outlet. Extension cord for welder will be more
important to you so welder can be used anywhere across garage.

 

[Speedy Petey]

Probably not "legal", but BY FAR the fastest and easiest solution !

Not code, but neither should draw any vampire amperage, if i was comfortable with the wire gauge and receptacles; I'd plug them both in and only use one at a time.

If you sell the property; remove the second outlet to eliminate any liability.

Any code citations to support this???

How is this any different from having two 1500W appliances plugged into the same kitchen counter circuit?

 

[Speedy Petey]

Why not just put 2 outlets on that circuit? It's easy enough to turn off your compressor before you fire up the welder. Worst case scenario both turn on at the same time & you pop the breaker.

By far the simplest and cheapest solution. And perfectly code legal.

 

[LS6 Tommy]

By far the simplest and cheapest solution. And perfectly code legal.

It is NOT code legal.

Tommy

 

[Norcal]

It is NOT code legal.

Tommy

According to the Urban Legend Code?

 

[MFortie]

Any code citations to support this???

How is this any different from having two 1500W appliances plugged into the same kitchen counter circuit?

I had one of our EE's at work look at this for me with regards to multiple 30a RV receptacles. Much to his surprise, the code allowed additional outlets on a 30 a /120v circuit - but no greater than 30a and we were specifically looking at a 120v circuit.

And no, I don't have the code reference...

 

[LS6 Tommy]

According to the Urban Legend Code?

Nope. NEC 210.23 (A) (2). Permanently fastened equipment must be on individual circuits if they exceed 50% of the circuit rating. If he uses the porper sized breaker, his compressor certainly will.

Tommy

 

[Git]

Nope. NEC 210.23 (A) (2). Permanently fastened equipment must be on individual circuits if they exceed 50% of the circuit rating. If he uses the porper sized breaker, his compressor certainly will.

Tommy

"Permanently fastened equipment"

I don't what kind of compressor he has - but there is a chance that it is a portable and not "Fastened in place"

Same thing with his welder, I don't think he is going to be bolting that down either?

How is this different from having a 20 amp circuit running to the kitchen sink and you have your garbage disposal and dishwasher plugged into the same outlet?

 

[LS6 Tommy]

"Permanently fastened equipment"

I don't what kind of compressor he has - but there is a chance that it is a portable and not "Fastened in place"

Same thing with his welder, I don't think he is going to be bolting that down either?


How is this different from having a 20 amp circuit running to the kitchen sink and you have your garbage disposal and dishwasher plugged into the same outlet?

If the compressor has no wheels or carry handles, it has mounting feet and it's plumbed to permanent piping it's considered "fastened". The fact that it's 240V tells me it's most likely not portable.

I wasn't arguing the welder.

You can't legally plug your diswasher and disposal into a duplex, nor can any other receptacle or light be on the same circuit. That's exactly what 210.23 (A) (2) prohibits.

Tommy

 

[Speedy Petey]

If the compressor has no wheels or carry handles, it has mounting feet and it's plumbed to permanent piping it's considered "fastened". The fact that it's 240V tells me it's most likely not portable.

I wasn't arguing the welder.

You can't legally plug your diswasher and disposal into a duplex, nor can any other receptacle or light be on the same circuit. That's exactly what 210.23 (A) (2) prohibits.

Tommy

Do you really believe what you wrote, or is it simply what someone told you once?

 

[Alchymist]

Remove the outlet and replace it with a small sub panel. Throw in two circuit breakers and wire an outlet to each one.

 

[wyliesdiesels]

If the compressor has no wheels or carry handles, it has mounting feet and it's plumbed to permanent piping it's considered "fastened". The fact that it's 240V tells me it's most likely not portable.

I wasn't arguing the welder.

You can't legally plug your diswasher and disposal into a duplex, nor can any other receptacle or light be on the same circuit. That's exactly what 210.23 (A) (2) prohibits.

Tommy

The 240v has nothing to do with it. The last shop i worked at had a portable compressor with a 4hp 240v motor on it. It had wheels on it.

thats incorrect. Its done all the time and is code permissable. The circuit is dedicated and the disposal and DW are cord and plug connected.

That code refers to a branch circuit that has fastened in place equipment as well as cord and plug connected equipment.

 

[LS6 Tommy]

The 240v has nothing to do with it. The last shop i worked at had a portable compressor with a 4hp 240v motor on it. It had wheels on it.

thats incorrect. Its done all the time and is code permissable. The circuit is dedicated and the disposal and DW are cord and plug connected.

That code refers to a branch circuit that has fastened in place equipment as well as cord and plug connected equipment.

I said it's not likely, not impossible.

Exactly. I said the "fastened in place" equipment has to be on an individual (dedicated) circuit. How about saying it like this, then: You cannot plug a dishwasher and a dipsosal into a duplex fed from the same breaker.

Tommy

 

[wyliesdiesels]

Whats incorrect is youre misinterpreting 210.23. A disposal and dishwasher on the same duplex doesnt violate that code. Go back and reread the code!

 

[LS6 Tommy]

Whats incorrect is youre misinterpreting 210.23. A disposal and dishwasher on the same duplex doesnt violate that code. Go back and reread the code!

Well, then 3 different inspectors need to reread the code, too.

Seriously, on my job I've had to have them rewired in two different towns. By three different inspectors. The "fastened in place" equipment cannot exceed 50% of the circuit rating. Dishwasher = +/- 9A. It's already above 50% on a 15A circuit even without a disposal.

Now, I'm completely on board with the idea that if the dishwasher in question is below 50% of the circuit rating, then you can also feed the disposal (or other items) from that circuit.

What MIGHT be legal would be to remove the bridge on the duplex receptacle and wire each outlet from a separate breaker. Then the breaker feeding the disposal could also feed other things. I can't say if that is allowable by code.

Tommy

 

[Thumper68]

The code Nazi's are going to freak but I have 3 240 outlets on one circuit in the shop. and even worse I have had 2 of the outlets in active use at the same time, tig welder and plasma cutter (Haven't tried the mig and plasma at the same time yet, have had both powered up at the same time though.)

And low and behold the world did not stop turning, or trip the breaker (Which is way more likely)

What I am saying is "Even though code says not to do it, it can be done with no ill effects as long as the proper wire size is used"

 

[Thumper68]

Well, then 3 different inspectors need to reread the code, too.

Seriously, on my job I've had to have them rewired in two different towns. By three different inspectors. The "fastened in place" equipment cannot exceed 50% of the circuit rating. Dishwasher = +/- 9A. It's already above 50% on a 15A circuit even without a disposal.

Now, I'm completely on board with the idea that if the dishwasher in question is below 50% of the circuit rating, then you can also feed the disposal (or other items) from that circuit.

What MIGHT be legal would be to remove the bridge on the duplex receptacle and wire each outlet from a separate breaker. Then the breaker feeding the disposal could also feed other things. I can't say if that is allowable by code.

Tommy

IMO most inspectors read the code the way they want to or the way their supervisor wants to, there have been many times where I have researched the code and had to point it out to the inspector in the book.

 

[LS6 Tommy]

What I am saying is "Even though code says not to do it, it can be done with no ill effects as long as the proper wire size is used"

IMO most inspectors read the code the way they want to or the way their supervisor wants to, there have been many times where I have researched the code and had to point it out to the inspector in the book.

I hear you on both of your statements and I agree. With inspectors it's always going to be "your mileage may vary". I've just found in general, I get better results when I don't second guess interpretations of not-so-clear codes. Considering I have to deal with these guys mutliple times a year and the safety of the students is the intended end result, I don't push it.

My point wasn't so much as to whether the code had real world merit or not, it was about the fact that the statement that it was "prefectly code legal" was made when I had actual experience and multiple unrelated inspector's judgements that it was not.

Tommy

 

[Mr_fixit]

I hat the threads when the code guys start arguing with what is and isn't code. Most garage journal guys would be going to a different website if we wanted to know the code...

 

[LS6 Tommy]

I hat the threads when the code guys start arguing with what is and isn't code. Most garage journal guys would be going to a different website if we wanted to know the code...

I bet the majority of the members here ask because they want to do it safe and right. Are there times when guys want to take shortcuts, sure. Are there ways to do things that are probably very safe but not necessarily code? No doubt. We all know code is overkill on many issues.

I wasn't "arguing" per se. When someone asks a question and I have relevant information I'm going to post it. When I'm wrong, I'm wrong and I try to own up to it. I don't think this was so much of a "who's right" issue as much as I was just listing my relative experiences.



Tommy

 

[Steevo]

This reply is to TommyR, the OP of this thread.
It is not meant to counter any of the compliance or code postings above, just to answer the question as to where to find a 240v "A/B" switch.

These are often used for heavy machines with reversible motors, but could be used for what you are asking very easily, and they are CHEAP.


http://www.ebay.com/itm/60-A-Drum-Switch-Forward-Off-Reverse-Motor-Control-Rain-Proof-Reversing-E456/281782894491?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3Ddc6144be442848c8b50cf302f314c072%26pid%3D100338%26rk%3D5%26rkt%3D14%26sd%3D170710854649

"Forward-off-reverse" could just as easily be "compressor-off-welder"

Safe and sane whether code compliant of not.

 

[Norcal]

I hat the threads when the code guys start arguing with what is and isn't code. Most garage journal guys would be going to a different website if we wanted to know the code...

With that attitude you have no business doing any electrical work.

 

[Norcal]

This reply is to TommyR, the OP of this thread.
It is not meant to counter any of the compliance or code postings above, just to answer the question as to where to find a 240v "A/B" switch.

These are often used for heavy machines with reversible motors, but could be used for what you are asking very easily, and they are CHEAP.


http://www.ebay.com/itm/60-A-Drum-Switch-Forward-Off-Reverse-Motor-Control-Rain-Proof-Reversing-E456/281782894491?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3Ddc6144be442848c8b50cf302f314c072%26pid%3D100338%26rk%3D5%26rkt%3D14%26sd%3D170710854649

"Forward-off-reverse" could just as easily be "compressor-off-welder"

Safe and sane whether code compliant of not.

Not the same thing, a reversing drum switch & a double pole, double throw switch are two different beasts.

 

[jmarkwolf]

Why not just put 2 outlets on that circuit? It's easy enough to turn off your compressor before you fire up the welder. Worst case scenario both turn on at the same time & you pop the breaker.

I have a similar situation.

I have a single 240V 20A outlet for my Bridgeport/VFD.

I just purchased a new 240V single-phase lathe that I'd like to plug into the Bridgeport circuit, without swapping plugs every time I use the other machine.

I was hoping I could simply replace the single receptacle with a 240V duplex receptacle.

The lathe only draws 8.5A at 240V, the Bridgeport draws even less. Each are less than 50% of the 20A circuit capacity. So it would appear both machines could run simultaneously and not exceed the circuit capacity, although I won't be doing so.

Looks like the link below is the solution. If it were a code violation I don't know why they are available.

https://www.platt.com/platt-electri...Duplex/Leviton/5824-I/product.aspx?zpid=35225