I want to run a sub-panel to my back yard and attach it to a block wall. The run is approx 70 ft. from my main panel. Does someone know if NEC has a min height requirement for the sub-panel installation?

 

The mounting height should be 6'6" to the center of the panel.You metioned it was to be in the backyard,if it is installed outdoors it must be weatherproof.

 

Ampz, please consult your code book. 6'6" to the center of the panel will put the top breakers higher than what is allowed by code.

To answer the original question, no, there is no minimum height.

 

John,I looked it up & I was off by 1" & it should be mounted in reference to the main :Art.404.8 {A}.......................They shall be installed so that the center grip of the operating handleof the switch or c.b. when in its highest positionis not more than 2.0 m {6ft 7in.}above the floor or working platform".

 

So just make sure that none of the breakers are above 6'7".

 

Had a brainfart,meant the center of the main

 

So, If I read the posts correctly, NEC has no min but states a max of 6'-7" measured from the working platform to the center of the box. Is this correct?
Thanks to all for your input, much appreciated.

 

No, measured to the top breaker. It's so "short" people can still reach all the breakers.

 

So, if no min. Is it reasonable to assume that 2', 3', or 4' from the ground or platform is OK? My block wall is only 6' high.

Also, if I have 200 amp main service and breakers in my box that total 250 amps without the 40 amp sub panel feed, will I exceed rated service?

BTW my sub panel will have a 20 amp breaker for a half size refrig and two 15 amp for two outside lights.

Since, I will be pulling a permit can I expect that on final inspection the county inspector will be looking for a watt load calculation to prove that I am within my 200 main service, once I add my panel? Our county inspectors are never available to answer any questions prior to the inspection. Short handed with very busy schedules. So a heads up will be appreciated.
Thanks!

 

No minimum means no minimum.

It doesn't matter what your breakers add up to. That's meaningless.

If your inspector wanted a demand load calculation, he probably will ask for it when your plans are submitted. It is unlikely that the addition of such small loads as you indicated will make a difference. If you'd like a more informed opinion, tell us how many finished square feet is your house, whether your major systems (heat, water heat, cooking, drying) are gas or electric, whether you have whole-house air conditioning, and whether you have a hot tub, pool, or any other unusual and large electrical consumers.

 

The only thing I would add about the minimum height, is try to make it a reasonably comfortable height for people to work at the panel. If you install the panel at floor level, it will not be much fun trying to work on it. (Unless you like lying on the floor!). So 2' sounds a little low to me.

The code only sets out the rules to follows; you can still use common sense within the rule set. In your case you should mount the panel as high as you can (since you only have 6’ to play with in any event)

 

This is a code requirement due to the fact that some equipmet manufacturers mount the main breaker vertically {perpendicular to the branch circuit breakers}.The measurement is not made from the top of the main c.b itself but from the highest position of the operating handle to the floor.If the main c.b. is mounted horizontally {parallel to the branch c.b.s}then the measurement is made from the center of the main.

 

ampz, I'm not sure why you keep talking about the main breaker. The article you cited is not talking about the main breaker. It's talking about all of them.

 

True, But,if a panel has any more than six switches it is required it have a main disconnect or circuit breaker right? So if the main is at the uppermost part of the bus isn't that where you would get the measurement from?

 

The main is not necessarily the uppermost breaker in the panel.

 

Also true,some panel interiors are convertable to allow the main to be at the bottom.So I'll re-phrase:The uppermost circuit breaker position should not be more than 6'7" from the floor or work platform.