A sub-panel from a sub-panel?

[Slowbuilder]

I am in the midst of a shop build (an addition to my existing shop - see my other thread), and since life wasn't complicated enough, my wife and I decided to purchase a Spa for Christmas.

Here's my difficulty - the existing shop has a 60a sub-panel in it which will likely eventually need to be upgraded to something like 100a, the spa will require 50a of 240v, and my main panel is full. Well, not COMPLETELY full, there is one 1/2 slot open, and one full-size breaker that could be doubled, giving 1 full-size slot open. Not enough to add a 50a 240v circuit for the spa.

There is a 125a capacity sub-panel mounted outside near the back of the house, that appears to be fed (daisy chained?) from the dryer circuit that terminates on the inside of the wall where it is mounted (someone has written on the inside of the panel "To shut off use Dryer breaker"). Caveat - I didn't do any of this wiring, and have no idea whether it was permitted and/or inspected, or done by a licensed electrician.

First question: If I upgrade the wire size appropriately, and put in a 125a breaker to feed the sub-panel on the house, can I then feed a new 100a service to a sub-panel in the shop from this sub-panel?

Second question: Can I then feed the dryer circuit (30a) from the 125a sub-panel on the house into the house? There would then be more than one panel feeding circuits in the house (though both panels would be controlled by the one disconnect in the main panel).

The objective here is to replace the existing 30a dryer circuit breaker with a 125a breaker to feed this 125a sub-panel, and then feed the dryer (30a), the spa (50a) and the shop (100a) from this sub-panel.

If I can't feed a sub-panel from a sub-panel, then I will size the feed for the sub-panel on the house for 100a or so, and feed the dryer and spa from this sub-panel, and then run a new feed for the 100a shop sub-panel from the main panel. The advantage of the first approach is that the feed for the shop will need to run almost directly past the 125a sub-panel; I could save the cost of that second run from the main to the sub for the shop feed.

 

[pattenp]

You can feed a subpanel from a subpanel from a subpanel from a subpanel...… until your hearts content. The issue you need to address is that the combined loads don't overload one of the upstream panels along the way.

 

[Norcal]

It might be possible to combine some breakers in that POS Challenger panel, it really depends if the bus stabs in the upper part of the panel are notched to accept quad breakers, Challenger breakers are no longer made so UL classified breakers have to be used, Eaton makes them.

 

[Engineer61]

Found out the hard way that current code in my area doesn't allow you to use all the spaces in your main panel, you have to have at least one free.
I can understand wanting to leave at least one (preferably more) free on new construction, but this was adding circuits to an existing structure - I put in a new circuit for more outlets in a basement room that was turned into a sewing room.

 

[wyliesdiesels]

Found out the hard way that current code in my area doesn't allow you to use all the spaces in your main panel, you have to have at least one free.
I can understand wanting to leave at least one (preferably more) free on new construction, but this was adding circuits to an existing structure - I put in a new circuit for more outlets in a basement room that was turned into a sewing room.

What code is that?

Is this a written local amendment?

Who told you this?

 

[Slowbuilder]

You can feed a subpanel from a subpanel from a subpanel from a subpanel...… until your hearts content. The issue you need to address is that the combined loads don't overload one of the upstream panels along the way.

Thanks patternp, I'll have to figure out what the expected concurrent load is, and whether or not it will require increasing the service from 200a. I have seen posts on this board about the possibility of adding a second meter for the shop, but apparently that's not an option - On my building permit for the shop extension, it lists (under "Required Special Conditions") "AN ACCESSORY BUILDING SHALL NOT HAVE A SEPARATE UTILITY METER FROM THE PRINCIPLE DWELLING. (MCDD 2012-13 & 2012 IRC E3601.2)." So that would require upgrading the existing service (and as a bonus, replacing the Challenger panel )

It might be possible to combine some breakers in that POS Challenger panel, it really depends if the bus stabs in the upper part of the panel are notched to accept quad breakers, Challenger breakers are no longer made so UL classified breakers have to be used, Eaton makes them.

Norcal, what do you mean by "combine some breakers" in the main panel? I have a breaker in the shop sub-panel that has 4 circuits, and is the size of two "normal" breakers. On this one, the top and bottom (at 30a) have a common trip via a handle tie and the 2nd and 3rd ones are independent. Is that what you mean? If that's the case, I could replace (say) the 30a dryer breaker with one of these (assuming the stabs are right- what should I look for?) and then move two other existing circuits to the inner 2 breakers, freeing up another full slot.

I know I took a chance in asking 2 questions in one post (and here I go again...), but is there any issue with feeding the dryer from the sub-panel?

Thanks for all your help!

 

[pattenp]

I know I took a chance in asking 2 questions in one post (and here I go again...), but is there any issue with feeding the dryer from the sub-panel?

Thanks for all your help!

There is no issue in itself of having the dryer on the sub-panel. It's still a matter of the sub-panel being sized accordingly for the anticipated loads.

 

[850xpeps]

There is no issue in itself of having the dryer on the sub-panel. It's still a matter of the sub-panel being sized accordingly for the anticipated loads.

Not only the sub panel but the main service I would assume if load is being added.

 

[Bretny]

You can run 120v circuits off a tandem breaker, i think thats what they call it. Takes up one slot anf has two 120v circuits on it. Doing this will allow you to gain spots for adding a proper GFCI breaker for your spa.

My spa came with a separate 6 spot sub pannel with gfci in it. Made it prety simple for me to hook up.

 

[pattenp]

Not only the sub panel but the main service I would assume if load is being added.

Yep.. upstream supply needs to handle all added downstream loads.

 

[nsula_country]

What code is that?

Is this a written local amendment?

Who told you this?

I'm curious too...

CT

 

[wyliesdiesels]

It doesnt make any logical sense

 

[hans109h]

It doesnt make any logical sense

I simply don't believe it.

Sent from my m8whl using The Garage Journal mobile app

 

[Engineer61]

What code is that?

Is this a written local amendment?

Who told you this?

The inspector did as I had pulled a permit and needed to have the work inspected. Surprised me as it doesn't make sense. Whether or not this is just a local addition to Aurora Colorado I don't know.

 

[mike93lx]

The inspector did as I had pulled a permit and needed to have the work inspected. Surprised me as it doesn't make sense. Whether or not this is just a local addition to Aurora Colorado I don't know.

it would be interesting to see what he provides if you request proof of the requirement. I'll bet it turns into something he wants...

 

[wyliesdiesels]

The inspector did as I had pulled a permit and needed to have the work inspected. Surprised me as it doesn't make sense. Whether or not this is just a local addition to Aurora Colorado I don't know.

Go ask him for written local amendment. I bet he wont have anything to show you.

 

[dscheidt]

The inspector did as I had pulled a permit and needed to have the work inspected. Surprised me as it doesn't make sense. Whether or not this is just a local addition to Aurora Colorado I don't know.

https://www.auroragov.org/business_services/building/adopted_building_codes

Says "2017 NEC". Not "2017 NEC with local amendments". I'm willing to bet your inspector is either a ***** or an *******, depending on whether he thinks it's really a requirement or just imposing his will on things.

 

[6768rogues]

NYS modifies the IRC with "enhancements" for our state. In our code, Section E3601.2 says, "One and two family dwellings shall be supplied by only one service." It does not say that an accessory structure cannot have a separate service, and it does not say that if more than one building exists on one property that each building cannot have a separate service. If I were you, I would check the exact language of the code myself.

 

[plain2car]

slowbuilder,
good news on the permit approval!!! ready to start when needed… on your electrical question, I guess there is not an option to upgrade (redo) the existing panal to a larger panel box with more breaker slots? I am not (as you know) an electrical guy... just askin' a silly question... LOL!!!

MERRY CHRISTMAS!!!

 

[plain2car]

slowbuilder,
good news on the permit approval!!! ready to start when needed… on your electrical question, I guess there is not an option to upgrade (redo) the existing panal to a larger panel box with more breaker slots? I am not (as you know) an electrical guy... just askin' a silly question... LOL!!!

MERRY CHRISTMAS!!!