Multiple feeders from one building to another 1

[ELMPE1]

I am working on a renovation of an existing school campus. The PE gym is currently fed from a breaker in a panel "MDP1" inside the adjacent (not connected) elementary school building. The school would like to add air conditioning to the gym (a packaged A/C unit setting on a pad outside the building). The existing gym panel "PE", located inside the gym, is too small for the additional load. The elem building panel "MDP1" is also too small to provide the feed, but there is a second panel "MDP2" adjacent to panel "MDP1" that does have sufficient capacity. Can I add a feeder from the elementary panel "MDP2" to feed the A/C disconnect (mounted on the wall outside the gym)?

 

[waross]

If you mount the disconnect switch on a post immediately adjacent to the pad mount A/C (rather than on the side of the building) and label it clearly as to the location of the feed it will be harder for the AHJ to condemn the installation. Talk to the AHJ before starting.

Bill
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"Why not the best?"
Jimmy Carter

 

[davidbeach]

What does the electrical engineer on the project have to say?

 

[ELMPE1]

waross,
Thanks for the comment. It will be up to the AHJ as you say; he may see the installation as separate from the building electrical with your idea.

 

[ELMPE1]

davidbeach,

The electrical engineer is referencing 225.30 allowing "only one feeder".

 

[alehman]

Is this a split system with an indoor unit? Are the existing and new circuits the same voltage and phase configuration?

Alan
----
"It’s always fun to do the impossible." - Walt Disney

 

[ELMPE1]

alehman,

Thanks for the response.

This is a packaged system with everything outside the building (only thermostat and some ductwork inside).

The existing buidling circuits are 120V1PH and 208V1PH fed from a 208V3PH panel located inside the building. The new packaged unit circuit is 208V3PH.

Thanks again,

 

[alehman]

I guess you could technically argue that it's not part of the building, but unless you can get the AHJ to agree, I'd have to stick with 225.30.

Alan
----
"It’s always fun to do the impossible." - Walt Disney

 

[ELMPE1]

alehman,

Thanks for the comment. I plan to upgrade the feeder so that the installation complies with 225.30.