Outdoor Electrical Box - Is this correct?

[WES51]

This box is mounted on the side of our detached garage. It currently services a single set of wires carrying 110V 20A.

I like to add a second conduit that would carry 220V 30A from the house to the garage.

Can I just simply add a conduit with the corresponding 30A wiring?

OR this is considered not safe for 240V 30A? E.g. box is too low and it needs to be moved higher or other issues?

 

[wyliesdiesels]

there is no code for height on a j box like that however you cannot have more than one feed to a detached structure.

you should run a feeder to the garage and set a subpanel

 

[grounded-b]

there is no code for height on a j box like that however you can have more than one feed to a detached structure.

you should run a feeder to the garage and set a subpanel

*** Can NOT have more than one feed to a detached structure

 

[wyliesdiesels]

*** Can NOT have more than one feed to a detached structure

damn typo

 

[WES51]

So what is this about the "feed"?

I'm not sure I understand. Does that mean I can't have a 20 Amp line and a 30 Amp line going into the garage?

Also, when I look up "feed", it seems to imply more serious power. So do my little 20A and 30A likes qualify as "feed"?

 

[wyliesdiesels]

So what is this about the "feed"?

I'm not sure I understand. Does that mean I can't have a 20 Amp line and a 30 Amp line going into the garage?

Also, when I look up "feed", it seems to imply more serious power. So do my little 20A and 30A likes qualify as "feed"?

correct.

any electrical circuit, no matter how low the ampacity is, qualifies as a "feed"

if you want more power, you will have to abandoned the 20a feed and run a new larger feeder to the garage

 

[tyme2par4]

So what is this about the "feed"?

I'm not sure I understand. Does that mean I can't have a 20 Amp line and a 30 Amp line going into the garage?

Yes. If you plan to run a new 30A line, just upgrade it to a 50A line, and put a small sub panel in the garage. Then run a new line from there to the receptacle.

 

[WES51]

Got it!

Sorry for asking, but is the code issue as it applies here just a minor violation or is there any real safety risk for running the wires as originally planned (in 2x separate conduits)?

After all, the way I understand it, if the garage was attached, this would be OK. Plus this is an old house and there are other (possibly bigger) issues that that may not meet today's standards.

By the way, the garage is about 20 feet from the house.

 

[Terry D]

Got it!

Sorry for asking, but is the code issue as it applies here just a minor violation or is there any real safety risk for running the wires as originally planned (in 2x separate conduits)?

After all, the way I understand it, if the garage was attached, this would be OK. Plus this is an old house and there are other (possibly bigger) issues that that may not meet today's standards.

By the way, the garage is about 20 feet from the house.

Whether minor or major, It is a violation of the NEC. The safety issue is that someone turning just the one breaker off and thinking the whole garage is dead. Starting with the 2020 NEC, which has not been adopted yet in California, It will be allowed to have more than one feed to an outbuilding. But there are certain requirements that have to be met. As for as me, being a electrical license holder, can not tell you it would be ok doing something against code. I guessing that this new circuit might be for a mini split, compressor or welder? I personally would use that existing conduit if possible, looks to be a 3/4, and pull in 3 (#6) copper and a #10 for the equipment ground and put a 60 amp sub panel out there. Probably more work than you expected, but you would be prepared for any future loads being added.

 

[Norcal]

Got it!

Sorry for asking, but is the code issue as it applies here just a minor violation or is there any real safety risk for running the wires as originally planned (in 2x separate conduits)?

After all, the way I understand it, if the garage was attached, this would be OK. Plus this is an old house and there are other (possibly bigger) issues that that may not meet today's standards.

By the way, the garage is about 20 feet from the house.

With multiple circuits going to a detached structure someone not familiar with the building may fail to properly disconnect power when working on it, just my opinion. This does not account for failing to test and verify that it’s disconnected like should be done.

 

[WES51]

Many thanks for the explanations and again sorry for my perhaps stubborn asking.

The house is very old with an old 100 Amp panel. The existing original old wiring is without ground, with ground being added here and there by the previous owner. So if we ever sell the house, all the electrical wiring should be overhauled/updated. Plus the way things go in our area, if we ever sell the house, it will be struck down anyway.

The 30 Amp line has been prepared long time ago and since waiting in a J box across from the garage at the corner of the house.

So I wouldn't mind waiting a few more years for the by @Terry D afroementioned 2020 code to take effect, that would allow me to do this. Then, I think I could also clearly label the breakers as Garage 1 and Garage 2.

By the way, the 30A line would serve only 1x single receptacle in the garage that would be occasionally used for a small compressor that is currently setup/wired for running on 110V 20A, but can be setup/wired for 220V 30A as well. Then in the very distant future, when I'm too old for working in the garage and have to sell all my old vehicles, then I would use this receptacle for possibly charging a by then 'mandatory' electric car.

 

[Norcal]

Many thanks for the explanations and again sorry for my perhaps stubborn asking.

The house is very old with an old 100 Amp panel. The existing original old wiring is without ground, with ground being added here and there by the previous owner. So if we ever sell the house, all the electrical wiring should be overhauled/updated. Plus the way things go in our area, if we ever sell the house, it will be struck down anyway.

The 30 Amp line has been prepared long time ago and since waiting in a J box across from the garage at the corner of the house.

So I wouldn't mind waiting a few more years for the by @Terry D afroementioned 2020 code to take effect, that would allow me to do this. Then, I think I could also clearly label the breakers as Garage 1 and Garage 2.

By the way, the 30A line would serve only 1x single receptacle in the garage that would be occasionally used for a small compressor that is currently setup/wired for running on 110V 20A, but can be setup/wired for 220V 30A as well. Then in the very distant future, when I'm too old for working in the garage and have to sell all my old vehicles, then I would use this receptacle for possibly charging a by then 'mandatory' electric car.

If you wait for CA to to adopt the 2020, you will need to add GFCI protection as well, it is not required for 240V circuits but will be under the 2020 NEC, also no CA PoCo offers 110 or 220 volts it is supplied at 120/240V.

 

[wyliesdiesels]

there is no such thing as a minor or major violation. its either a code violation or not

 

[WES51]

If you wait for CA to to adopt the 2020, you will need to add GFCI protection as well, it is not required for 240V circuits but will be under the 2020 NEC, also no CA PoCo offers 110 or 220 volts it is supplied at 120/240V.

Yes, GFCI breaker is already in the plans.

I will soon make some adjustments to the driveway and walkway layouts, which will include breaking the concrete at this location and replacing it with stone slabs. By that occasion I plan to lay the conduits with the corresponding wiring. Then the wiring can just lay there UN-connected and wait for the code to take effect.

Besides, there is no hurry in connecting the 30 Amp part of the wiring and making it operational. I'm happy with my compressor as is. So the 30 Amp would really be only as bonus and for possible future electric car charging.

 

[JKJEFF]

Why be so stubborn? A small sub panel is about $70.00. Then you are done, correctly.

 

[wyliesdiesels]

I agree.

Why resist putting in a subpanel?

What will you do when you need another circuit?

A subpanel is so much easier.

Youre actually spending more money and effort doing it your way than it would take to just put a subpanel in.

 

[WES51]

As far as resisting the sub-panel idea, like I have said: the 30 Amp line is ALREADY WAITING in the J box at the corner of the house.

This is not a new construction where I have the luxury of designing the electrical system. We live in this house and I can't just tear up the walls to route a 50 Amp line to the corner of the house. Especially since all I need is one additional single 30 Amp receptacle.

So we are not talking about a small extra difference of a sub-panel purchase. Plus if the code will soon allow for my original plan anyway, then I rather wait for that, instead of tearing up the walls for pursuing the sub-panel idea. Especially since I'm not in a rush.

Anyhow, many thanks for everyone for all the great input and suggestions. I'm sure not trying to be the one who asks and then does not listen. But unfortunately I have some limits to what I can do and adding a sub-panel in my current situation just seems to be beyond that.

 

[wyliesdiesels]

Whats the HP rating on the compressor? If its more than about 3HP it will need to be hardwired unless you use pin and sleeve plugs.

 

[jeepxj]

would the multiple voltages apply here? he has a 120 circuit and wants to add a 240v circuit?
225.30(D)



also:

In the 2020 NEC, Section 225.30(B) was revised to allow multiple feeders originating in the same panelboard, switchboard, or other distribution equipment, and terminating in a single disconnecting means at the load end.

225.30 Number of Supplies
Outside Branch Circuits and Feeders
6. Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability
7. Electric vehicle charging systems listed, labeled, and identified for more than a single branch circuit or
feeder
8. Docking facilities and piers



that is really interesting about the EV chargers. I didnt realize they changed it. so in a detached garage I can have an EV charger and a basic 20a circuit for lights/garage door opener without going full subpanel. if im reading this right.

 

[WES51]

Whats the HP rating on the compressor? If its more than about 3HP it will need to be hardwired unless you use pin and sleeve plugs.

The compressor is a 30 Gallon compressor, portable type by design. It is only going to use less than 30 Amps. So I hope a standard 30 Amp connector will do.

 

[Terry D]

would the multiple voltages apply here? he has a 120 circuit and wants to add a 240v circuit?
225.30(D)



also:

In the 2020 NEC, Section 225.30(B) was revised to allow multiple feeders originating in the same panelboard, switchboard, or other distribution equipment, and terminating in a single disconnecting means at the load end.

225.30 Number of Supplies
Outside Branch Circuits and Feeders
6. Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability
7. Electric vehicle charging systems listed, labeled, and identified for more than a single branch circuit or
feeder
8. Docking facilities and piers



that is really interesting about the EV chargers. I didnt realize they changed it. so in a detached garage I can have an EV charger and a basic 20a circuit for lights/garage door opener without going full subpanel. if im reading this right.

120 and 240 single phase are derived from the same system. They are not separate voltages. A example is having a 3 phase delta 240 or 480 system and a single phase 120/240. Those are separate voltages derived from two different systems and would be allowed feeding the same building

 

[jeepxj]

120 and 240 single phase are derived from the same system. They are not separate voltages. A example is having a 3 phase delta 240 or 480 system and a single phase 120/240. Those are separate voltages derived from two different systems and would be allowed feeding the same building

technically 240 and 480 are derived from the same system. All coming in from the same grid. its just a question of where that is occurring that matters for this context it would appear.

 

[slow]

Did you run 3 or 4 wires to your junction box at the house? a 30 amp 240 with neutral may be plenty to feed the whole garage with a subpanel.

 

[WES51]

Did you run 3 or 4 wires to your junction box at the house? a 30 amp 240 with neutral may be plenty to feed the whole garage with a subpanel.

The wiring is coming off an old 3 wire 240V 30 Amp washer/dryer connector, that is nearby and that has been sealed and relieved of it's function as such.

30 Amp however won't be enough to serve peak electricity needs of the garage.

 

[CGT80]

30 amps at 240v is 3x the amperage/wattage you have with a 20a 120v feed that is there now, when it comes to 120v devices.


Your air compressor likely won't draw more than 10 amps and you will have two legs of 30 amps with a sub panel. That leaves up to 20 amps on each leg, still double what you have now. If you added a car charger that required a 30 amp breaker and then only needed lights in the garage at that point, it might work.


For now, the sub panel with a 30 amp feed should work. On the other hand, if you have enough power for what you are doing now, then installing the sub panel now and wiring your air compressor for 240v isn't going to gain you anything. If you plan to pull up concrete later, then it makes sense to run large enough conduit to pull whatever you need.



I just changed out my garage from #6 50 amp feed to the sub panel, to #4 copper thhn and 1.5" PVC conduit since my tig welder will pull 104 amps at 230v ( 50% output wasn't good enough, but I don't need the full 460 amp output it is capable of, so #4 will work) and my air compressor pulls 30amps at 240v while running and 169 amps at start up, for a real 5hp motor. The #4 copper was free, otherwise I would have used #2.

 

[wyliesdiesels]

The compressor is a 30 Gallon compressor, portable type by design. It is only going to use less than 30 Amps. So I hope a standard 30 Amp connector will do.

gallons means nothing in the NEC. what is the HP rating as listed on the motor nameplate? If it doesnt list it or lists SPL, then what is the FLA as listed on the motor nameplate

also any connectors need to be rated for the same or greater HP as the motor HP rating. Amps mean nothing on the connectors ratings.

most 30a connectors are rated for 2HP

 

[mmotodad]

Just a DIYer myself but I will throw in my 2 cents - if your portable compressor runs on 110 at 20A or under, it will run on roughly half the amperage at 220V (10A or less). You can search here on GJ for a thread debating whether it is worth changing a 1 - 2 HP motor to 220V. Some say it runs smoother at 220. I have an old 1 1/2 HP compressor and personally see no difference between 110V and 220V. Also it becomes no longer as "portable" with a 220 plug on the end. The 30A circuit you want to extend, is it an old non used circuit in the house or new wiring that you placed while doing other remodel work in anticipation of pulling to the garage? 2 hots and a ground only?

 

[WES51]

I think I shouldn't dive much deeper into particular usage details, that may or may not happen and are in the future anyway.

My main focus was on the proper connection of the garage to the house and that seem to have been answered already.

I like to thank again for everyone for all the help and great suggestions that went even beyond the scope of my original question.

 

[Norcal]

If this circuit is taken from a 3-wire dryer circuit, & the 3rd wire has white colored insulation, it cannot be reidentified as green.

 

[wyliesdiesels]

If this circuit is taken from a 3-wire dryer circuit, & the 3rd wire has white colored insulation, it cannot be reidentified as green.

good catch

 

[alfredeneuman]

If this circuit is taken from a 3-wire dryer circuit, & the 3rd wire has white colored insulation, it cannot be reidentified as green.

....but it can have the insulation stripped off wherever it's visible and qualify for a grounding conductor because it's bare.

 

[Terry D]

....but it can have the insulation stripped off wherever it's visible and qualify for a grounding conductor because it's bare.

Wouldn't it have to be bare its entire length since the insulation on the rest of it is not green or green with yellow stripe(s), technically speaking.

 

[Norcal]

Wouldn't it have to be bare its entire length since the insulation on the rest of it is not green or green with yellow stripe(s), technically speaking.

Kind of hard to do with NM cable.

 

[dave*99]

If this circuit is taken from a 3-wire dryer circuit, & the 3rd wire has white colored insulation, it cannot be reidentified as green.

And he would need 4 wires if he were to install a 120/240V subpanel in the garage.

 

[alfredeneuman]

Wouldn't it have to be bare its entire length since the insulation on the rest of it is not green or green with yellow stripe(s), technically speaking.

Woops
I double checked and it only applies to #4 and larger....My mistake
(Norcal made a good point by saying that it would be impossible to do with NM)

 

[Terry D]

Woops
I double checked and it only applies to #4 and larger....My mistake
(Norcal made a good point by saying that it would be impossible to do with NM)

I know, i was just being silly

Sent from my SM-G960U using The Garage Journal mobile app

 

[Bert_]

If I needed a 240 circuit and there was already a wire close by I would have zero issue taping the white wire green on an existing 3 wire w/o ground cable.

Obviously nobody is going to do it on a new install but it's such a minor detail it doesn't matter.

 

[Bert_]

To the op if you're going to the work to dig a new wire out there then just do it right. It's not that much more work.

 

[CJ7VFR]

there is no code for height on a j box like that...

He should check with his local municipality to see if they have any codes that have a minimum height requirement for installing outside electrical boxes.

Our local municipality requires that all outside junction boxes, pull boxes, LB's, and outdoor weatherproof receptacle housings be installed at a minimum height of 24 inches from the bottom of those items to the ground.

I had to do this for my shed when I ran the power to it from the house. Both the LB coming out of the house and the weatherproof box on the side of the shed had to be a minimum of 24 inches off the ground.

The inspector who came out from the township to check it all out even measured it to make sure. He said they have this requirement because of the possibility of rain water splashing up and onto those items, and they want to keep that at a minimum.

Jim