Detached Structure Question

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mark32

mark32

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Currently in NJ
Hi,

A friend built a small detached addition and has an existing 100 amp sub panel mounted 5' off the building that serves pool equipment. My question is can I install a MLO panel (Feeding it from said sub panel) inside the building or do I need a main breaker panel because the existing sub in not actually mounted on the building?
 
An additional note to what has already been said.....is make sure the existing panel for the POOL itself has been installed properly before trying to add from it. Read over 680.25 as well to be sure.

Yes, that seperate building is a structure as is that location where the pool panel is already installed....both are structures and Art.225 will apply as stickboy already stated.
 
Okay, I just read 225.32 and it states the disconnecting means shall be installed either inside or outside of the building, not "On the building" as I intially thought. Thus, I believe the breaker in which I will feed the new building with (Located in the outside sub panel) should satify this requirment, maybe I'm wrong. I will also sink ground rods from this panel as per 250.32(d)
 
mark32 said:
Okay, I just read 225.32 and it states the disconnecting means shall be installed either inside or outside of the building, not "On the building" as I intially thought. Thus, I believe the breaker in which I will feed the new building with (Located in the outside sub panel) should satify this requirment, maybe I'm wrong. I will also sink ground rods from this panel as per 250.32(d)
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IMO, it wont count because the disconnect has to be installed nearest the point of entrance of the conductors.... 225.32, The existing sub-panel is not the nearest point.

And yes you will need a Grounding Electrode at the building and at the pool panel if they are not already installed.
 
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stickboy1375 said:
And yes you will need a Grounding Electrode at the building and at the pool panel if they are not already installed.
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If the structures are 5' from each other then the ground rod (I presume) for the pole can also be used for the building. In other words, You wouldn't need 4 ground rods just 2.
 
mark32 said:
A friend built a small detached addition and has an existing 100 amp sub panel mounted 5' off the building that serves pool equipment. My question is can I install a MLO panel (Feeding it from said sub panel) inside the building or do I need a main breaker panel because the existing sub in not actually mounted on the building?
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I believe the intent of 225-31 & 32 is to open the phase conductors in an emergency. 225-32 "The disconnecting means shall be installed either inside or outside of [rather than 'on'] the building". You may ask your inspector because you're application is so close and this seems subject to interpretation.

Also you'll most likely need a 4W feeder -- 250-24(A)(5) & 250-142(B) -- unless you meet all the criteria of 250-32(B)(2).

I also recommend you calc. the existing sub panel to qualify additional load.
 
Thanks for the replies.

Stickboy, I dig what you're saying about the location of the main. The same thought occurred to me after I made the post.

Tryinghard, I'm glad I'm not the only one that feels this isn't a cut and dry scenario. I haven't seen the job yet but I'll be sure to check the existing feeder size and load.

One more question, can I run the GEC to the ground rods from the outside panel or must I take it from the inside panel?
 
What's up Stickboy,

The panels in question would be the existing panel that sits outside this new addition or the new one I will install inside the addition.
 
mark32 said:
One more question, can I run the GEC to the ground rods from the outside panel or must I take it from the inside panel?
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The electrodes have to connect, and you will most likely have a 4W feeder that will include an equipment-grounding conductor separate from the neutral, this EGC will connect the electrodes.
 
mark32 said:
What's up Stickboy,

The panels in question would be the existing panel that sits outside this new addition or the new one I will install inside the addition.
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Both need to connect...., the existing pool panel should already have ground rods, so hopefully you can find them and use them for your new panel.
 
No no no, I got all that in regards to GECs and ground rods and bonding and separate neutrals and eg's at sub panels etc. I wanted to know if I can just run the gec to my newly installed (If there are no existing ones) ground rods from the existing outside panel, which would be a very short run, or must I run it from the yet to be installed panel that will be inside the new addition. Right now I am counting on finding a 4 wire feeder and no ground rods, just an assumption.
 
mark32 said:
No no no, I got all that in regards to GECs and ground rods and bonding and separate neutrals and eg's at sub panels etc. I wanted to know if I can just run the gec to my newly installed (If there are no existing ones) ground rods from the existing outside panel, which would be a very short run, or must I run it from the yet to be installed panel that will be inside the new addition. Right now I am counting on finding a 4 wire feeder and no ground rods, just an assumption.
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You are not required to install more than 2 rods for an electrode and your building & source structure are extremely close together, GEC's are supposed to go to each panel then connect through equipment bonding. If you take the rule in 250-50 & 32 to its extreme you need an electrode at each. In my opinion I think you have your electrode system for each and you may even have your disconnect if it is that close, ask your inspector.

The electrode is mainly for lightning but also an over-voltage, lightning is just looking for earth and over-voltage is looking for its source (usually utility transformer XO). Because lighting may strike the building anywhere it is best to keep the GEC short as possible and it needs to terminate at the main, you want these voltages to find a way out of you system ASAP.

As example if you had a ufer at the new building it would not satisfy code for the needed electrode at the source panel structure. The source panel structure has to have an electrode if it doesn't install it and it will satisfy code to both structure and building because they are so close.
 
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Thank you tryinghard for your time and insight. Things will become more clear when I get on site. The job is for a friend of a friend and he pulled a homeowners permit as he planned on doing the wiring himself. After speaking with me though he decided it was too much for him so I am really a consultant on this one as he's going to do most of the labor and I will direct him as needed. Thanks again.
 
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