20A 250V duplex receptical code question

[Radix2]

I am running a MWBC through my machine area so that I can configure my outlets for 120 or 240V as needed. Running mostly 2 gang boxes.

In looking ahead to plates, the only choice with a 1.4" opening (20A/250V single outlet) double plate is with a duplex. This always worked fine when the 120V side was a simple outlet, but now that we need GFCI, what is needed is a 1.4/decora - which is not made unless you use the snap together style.

Then I noticed that the 20A/250V receptacle is made in a duplex version - Is this permitted on a 12ga/20A circuit ? Code ref?

 

[sberry]

My mind is elsewhere but I personally would skip all the mwbc circuits in a simple shop, run a new wire dedicated for a machine or circuit when its needed and keep it straight forward. This all makes sense for long heavily loaded circuits, as it is right now 240 doesn't need to be gfci and is wayyyyyy easier especially when the savings are so small.

 

[Radix2]

Well, as far as I can see, the 15,20A 250V duplex receptacles can be used just like the 120V ones.

Not clear to me why then the single outlet 250V versions are more commonly stocked...given the 1.4" hole plates are so limited.

Anyone disagree or had any issue with using the 250V duplexes in residential shop applications?

 

[sberry]

I was actually going to look at a woodshop master wired but I forgot. You may wire multiple machines on same circuit provided they are rated for the breaker rating. I don't do this enough to be familiar without looking it up or having it splained to me and tired enough I don't feel like thinking it thru.

 

[wyliesdiesels]

Well, as far as I can see, the 15,20A 250V duplex receptacles can be used just like the 120V ones.

Not clear to me why then the single outlet 250V versions are more commonly stocked...given the 1.4" hole plates are so limited.

Anyone disagree or had any issue with using the 250V duplexes in residential shop applications?

u have a link to a duplex 250v outlet?

Also, if you are under the IRC/IBC, multiple outlets on a 240v circuit above 20a are not allowed so keep that in mind if you do higher amp outlets.

The problem with doing a MWBC for 240v is that 120v outlets require GFCI protection, so u would have to spend lots of money on double pole GFCI breakers.

A MWBC in a garage is gonna be more expensive, than individual circuits.

 

[Radix2]

u have a link to a duplex 250v outlet?

Also, if you are under the IRC/IBC, multiple outlets on a 240v circuit above 20a are not allowed so keep that in mind if you do higher amp outlets.

The problem with doing a MWBC for 240v is that 120v outlets require GFCI protection, so u would have to spend lots of money on double pole GFCI breakers.

A MWBC in a garage is gonna be more expensive, than individual circuits.

https://www.amazon.com/dp/B01CGW17ZQ/?tag=atomicindus08-20

https://www.westwayelectricsupply.c...wire-br.html?gclid=CK6Gycvw4dECFVa2wAodcusOZg

They all seem to make them, leviton, cooper, etc. I also see single and duplex in decora format. https://www.google.com/search?q=20a...7-HRAhWm14MKHY08AugQ_AUIBygB&biw=1024&bih=672

Yes, GFCi req throws a monkey wrench into the symplicity of just running 12-3 everywhere and being able to choose either 120/240 at each spot.

Gfci 20a dbl pole breakers for my panels are about $90 - so unless you have a ton of outlets and no feed through they don't make sense.

I'm doing it a couple ways. In some spots just running the 12-3 and I will have to put gfci recepticals for the 120s not easily fed through. In others I ran the 12-3 to the location then broke it down into gfci protected feeds and 240 feeds on 12-2 from that point.. this is the cheapest method but a wire hog.

I think the mwbc makes sense because it is the simplest way to have flexibility at each spot. It would cost more to run it individual since the same functionality would require 2 single pole breakers AND a double pole breaker for the same run.

Many of my machines are 240, so I put 2gang boxes and many have a 240 and 120 side by side.

Don't need all the 240 sockets, but the plate issue makes the 250v duplexes a solution.

I believe they make or made combo duplexes with 120 on top and 240 on the bottom.

 

[davetulk]

If its surface mounts you can get plates here:

http://www.garvinindustries.com/ele...-device-rings/industrial-surface-covers/g1940

http://www.garvinindustries.com/ele...-device-rings/industrial-surface-covers/g1952

 

[Marctrees]

Radix - You are totally crawling down a totally unnecessary rabbit hole.

REALLY seems to be yet another case of over analyzing, trying to re invent the wheel.

Wanting to be weird totally non standard, re enginneering cause standard convention is not good enough or something.

Is this a Auto assembly plant, or a small shop???

You said "residential", then you have "many" machines that need 230.

Like 2 diff things.

I was a MN elect contractor for 15 yrs, till 20 yr ago.

The posts above are very strange to me.

Why try to re invent the wheel ?

Jacking around w weird plates like above is really, ...... WHY ???????????

120/ 240 outlets in same box WHY ?????

Really odd.

You run ckts for your regular 120 receptacles for general use, , 3 wire split if you wish, then your 230 outlets separately, to where they are needed.

NMB, or conduit w diff ckt pulls, whatever applies to you.

Too tired to understand what the hell this is all about.

Maybe should be just hired out.

Marc

 

[Radix2]

I don't know if Marc is the only one confused, but there is nothing particularly complicated about what I am doing so I will explain.

The issue being addressed is two part.

One - I want flexibility to move and set up machines in the future, I don't want to have to figure it out exactly now before actually working in this shop.

Two - I don't want to do surface mounted conduit - which is great for future modifications.

So I need a solution that is flexible and all in place behind the drywall.

So what I am doing is putting up two gang boxes about every six feet or so around the machine areas and running from a 2pole breaker 12-3 from box to box.

So at every box I can but in either 120v or 240v recepticals and the 120v can be on two different phases as desired. It is very simple and flexible.

GFCI requirements add cost or some extra wire, but that is another discussion.

 

[wyliesdiesels]

I don't know if Marc is the only one confused, but there is nothing particularly complicated about what I am doing so I will explain.

The issue being addressed is two part.

One - I want flexibility to move and set up machines in the future, I don't want to have to figure it out exactly now before actually working in this shop.

Two - I don't want to do surface mounted conduit - which is great for future modifications.

So I need a solution that is flexible and all in place behind the drywall.

So what I am doing is putting up two gang boxes about every six feet or so around the machine areas and running from a 2pole breaker 12-3 from box to box.

So at every box I can but in either 120v or 240v recepticals and the 120v can be on two different phases as desired. It is very simple and flexible.

GFCI requirements add cost or some extra wire, but that is another discussion.

Heres the thing you arent considering with the GFCI. Since 240v GFCIs arent available as an outlet, u have to use a breaker which u already know. The problem with this is if u trip the GFCI breaker due to an issue on a 120v outlet, u loose power to everything.

I dont know about u, but this can be frustrating and cause issues with the material u are working on if the machine suddenly loose power.

The added cost also doesnt make sense.

For what u will spend on 120v/240v GFCI breakers, u could use for surface mount conduit or extra NM-b to have separate 120v and 240v circuits.

 

[Marctrees]

Radix - Sorry for being needlessly snarky in my previous post, was late night.


OK, objective understood.

It would be great to get advice from a commercial/ light industrial construction electrician very experienced in laying out this kind of thing, using big enough conduit for future expansion.

Plan everything so you can fish in a new ckt to anywhere in the conduit "tree".

Usually, a new outlet box is nippled from an existing for a different outlet.

Anyway point is, a guy that normally works this stuff may save you some headache both current and future.

Right of the bat, 6' spacing is maybe overkill, like 10' should be more that adequate.

Marc

 

[Radix2]

[/b]

Heres the thing you arent considering with the GFCI. Since 240v GFCIs arent available as an outlet, u have to use a breaker which u already know. The problem with this is if u trip the GFCI breaker due to an issue on a 120v outlet, u loose power to everything.

I dont know about u, but this can be frustrating and cause issues with the material u are working on if the machine suddenly loose power.

The added cost also doesnt make sense.

For what u will spend on 120v/240v GFCI breakers, u could use for surface mount conduit or extra NM-b to have separate 120v and 240v circuits.

You may have missed it above (see my response to your inquiry about 250v duplex), but I concur. GFCI dbl pole breakers are about $100 so it doesn't make sense to use them.

So I am using GFCI outlets and feeding that ahead where I want 120 outlets. (The MWBC converts back to a two wire feed after the GFCI)

In a couple spots I have an additional GFCI outlet or two than would be strictly required, but the extra cost is nothing compared to 3 or 4 dbl pole GFCI breakers!


I appreciate that this method is a bit different than normal and probably over flexible for 250v(20a) outlets ... but it is a bit of a reaction to needling to get this done under an electrical permit I have open. I would have rather left the workshop detail and electrical to be a separate project that would let everything be customized to what is needed as many suggest, but due to trying to keep trades synchronized, I decided to build in extra flexibility ( at some additional cost).

But I don't think the cost is more. For the same result, conventional topology would need more total wire and more breakers (3x the beakers and 2x the panel spaces- each MWBC dbl pole becomes 1 dbl pole+2sngl pole). Now, it would be fair to say that the number of circuits could (should) be reduced to get back some of the cost, but I don't see a net savings at the end.

I can see why electricians would not do it this way. They make money and get quality by doing set patterns and doing it fast. It is not worth any extra thinking or complexity to do a special deal for a workshop.

So... I guess it still fair to say that thete is no NEC restriction on using 250v duplex recepticals instead of the common 1.4" single version?...

I did also see a 250v single in the decora format that would work.

 

[Radix2]

If its surface mounts you can get plates here:

http://www.garvinindustries.com/ele...-device-rings/industrial-surface-covers/g1940

http://www.garvinindustries.com/ele...-device-rings/industrial-surface-covers/g1952

Thanks Dave!

I am looking for flush mount, but maybe another crazy will be helped.

 

[Radix2]

Radix - Sorry for being needlessly snarky in my previous post, was late night.


OK, objective understood.

It would be great to get advice from a commercial/ light industrial construction electrician very experienced in laying out this kind of thing, using big enough conduit for future expansion.

Plan everything so you can fish in a new ckt to anywhere in the conduit "tree".

Usually, a new outlet box is nippled from an existing for a different outlet.

Anyway point is, a guy that normally works this stuff may save you some headache both current and future.

Right of the bat, 6' spacing is maybe overkill, like 10' should be more that adequate.

Marc

No problem, I appreciate a critical review.

My last shop was wired the same way and it works great and is very simple in the old pre GFCI days. Last time I used the snap together plates that let you put a 1.4 next to a duplex (they still have these at Lowe's). I also see that Hubbell and others make the 1.4/duplex plates, but they are hard to find.

So the 250v duplex are interesting as an alternative.

 

[davetulk]

These what you are looking for?

http://www.kyleswitchplates.com/round-outlet-plus-decora-rocker-gfci-receptacle-cover-plates/