Inverter placement question

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I'm part of a team constructing a small solar house. The architects insist on putting the pv inverter above the panelboard to conserve space. Would this violate the NEC?
 

charlie b

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Seattle, WA
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Electrical Engineer
It is generally OK to put things above or below a panel if, and only if, they are associated with the panel. In this sense, an inverter is associated with the panel, so it fits into the "OK category." However, the front face of the panel should be further from the wall than the front face of the inverter, or they may be in the same plane. There needs to be a space reserved, a space called "the working clearance," and the inverter must not interfere with this space. The space must be at least 30 inches wide, or the width of the panel, whichever is greater. It must be 36 inches deep (presuming a voltage to ground of 150 volts or less), and it must be 78 inches high. The reference is NEC article 110.26.

Welcome to the forum.

 

chris kennedy

Senior Member
Location
Miami Fla.
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60 yr old tool twisting electrician
osu_solardec said:
The architects insist on putting the pv inverter above the panelboard to conserve space.
Pretty poor design IMO. The architects don't have to get the conduits/cables past the inverter and into the panel. If you decide to flush mount one piece and surface mount the other don't over look this when you read 110.26

other equipment that is associated with the electrical installation and is located above or below the electrical equipment shall be permitted to extend not more than 150 mm (6 in.) beyond the front of the electrical equipment.
Edit: Welcome to the Forum. And spelling
 
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Thank you for responding. I realize it's a bad design, but unless it specifically violates code they are not willing to yield. Given that the inverter is 9.5 inches deep, it probably won't work. Thank you for the help.
 

acrwc10

Senior Member
osu_solardec said:
Thank you for responding. I realize it's a bad design, but unless it specifically violates code they are not willing to yield. Given that the inverter is 9.5 inches deep, it probably won't work. Thank you for the help.
If the panel is surface mount ( given a standard 3.5'' depth panel ) and so is the inverter at 9.5 '' depth it meets the minimum on the other hand if the panel is semi flush it won't meet the depth maximum any longer. I can't believe the house is so small that there is not enough room for both side by side. :D
 

rexowner

Senior Member
Location
San Jose, CA
I really have to agree with Chris here wrt practicality.

It sounds like this is a Solar Decathlon entry, which is going
to be judged by objective and subjective criteria, and locating
an inverter over a panel sounds like a poor aesthetic and
practical choice, which is only going to hurt the team effort.

I'm guessing the inverter has an LCD with relevant information,
and placing it on top of the panel could make
it too high for many to read. I am not sure if by "panelboard"
you mean where the meter is, but if so, then utilities typically
have practical height limits. Putting the inverter above this
height seems like a really bad design from a practical
standpoint. I assume you are building a model house
for future innovation, so starting with problems is not
the way to go.

Good luck with your entry!!!
 
In order for a guy to work on the inverter , he would need a ladder, therefore its not readily accesible, what inverter is it, does it have the dc disconnect attached to it, if it does then you wouldn't want it higher than 6foot 6. Tell the inspector that.
 

iwire

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Location
Massachusetts
duluthelectrical said:
In order for a guy to work on the inverter , he would need a ladder, therefore its not readily accesible, what inverter is it,
Lower the panel?

The panel can be on the ground.

I don't see the big deal, when I have had to mount a deep ATS below a shallow panel I simply built the panel out flush with the ATS.

My suggestion would be to place the inverter below the panel that has been spaced out to match the inverter.

I would keep the panel as high as possible (404.8(A) 6'-7" to the top handle).

The customer wants what they want. If what they want is legal and they are willing to pay for it IMO the tradesman should do what the customer wants even if the tradesman does not like it.
 

DownRiverGUy

Member
Location
Canton, MI
Consider the weight of the unit as well.

Depending on the manufacture the Inverters can weigh well over 100lbs.

If you have to remove the inverter for transport that could be 3+ times you'll have to remove a large piece of equipment off the wall. Make sure that the wall can support that kind of weight especially if it's staying on for transport.

Where are the knockouts of the Inverter unit and how will they feed the Panel Board?

Fight for the space you need! This is dangerous equipment and you do not want to work with it inside a small awkward space. A team last year had a significant injury (2nd degree burns) because their electrical room was SO TINY.

OSU what position are you in the project? Electrical Engineer? Electrician?

If John Wiles is still working with the Solar Decathlon you should contact him ASAP with any questions or concerns. He will be giving the final say on any designs and is more than happy to help when he can.
 

iwire

Moderator
Staff member
Location
Massachusetts
DownRiverGUy said:
A team last year had a significant injury (2nd degree burns) because their electrical room was SO TINY.
In my opinion they got hurt because of actions of their own.

Stacking electrical equipment and shoe horning it in is both normal and legal assuming the end result complies with 110.26. (And any ventilation needs)

We sometimes have to stack transformers, we don't want to but we can only use the space the architects have given us.
 
tallgirl said:
Inverters make heat. Therefore, they are going to be happier LOWER in the space than higher.
Nope, you want the heat producers ABOVE the non-heat-producers.

The inverter requires both adjustments and clearences for heat dissipation.
- The adjustment would requirethe keypad and display panel portion to be no higher than ~5-6'.
- Heat clearences around and behind the unit should be listed with the manufacturers installation instructions.

Another limiting factor on locations would be the EM/RF interference with other electronics. Cheap drives meet lesser standards or even ignore any of the cited issues and will offer no guidance.
 

iwire

Moderator
Staff member
Location
Massachusetts
weressl said:
Cheap drives meet lesser standards or even ignore any of the cited issues and will offer no guidance.
FWIW this is a house not a business and it's not exactly a drive, it is a solar power inverter. :smile:

Here is the OP

I'm part of a team constructing a small solar house. The architects insist on putting the pv inverter above the panelboard to conserve space. Would this violate the NEC?
In straight forward terms, the answer is no. It does not violate the NEC assuming compliance with 110.26. :smile:
 
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