[DesertHawk]

I am in the process of installing a natural gas-powered outside tankless water heater. It's a small house, so I want it installed on an exterior wall to save space inside. The issue I'm running into is clearances around the heater. I have a very small spot where it can be installed on the back of the house, and in order to meet the 12" away-from-a-window requirement, I would need to mount it right next to my main electrical service panel (and electric meter). I have found no code requirements about mounting next to an electrical panel. All breakers are enclosed in the panel and the wiring is all enclosed in conduit, so I'm not sure this would be a problem. The only thing I found refers to the gas meter itself, which must not be installed within 3 feet of an electrical panel. That's fine, as my gas meter is on the other side of the house. I guess the code by which I should abide is for 3/4" gas lines themselves, if any code exists for running them in close proximity to electrical panels. That's the only thing I can think of!

 

[chandler48]

You must maintain a 3' clearance around your electrical panel, so installing anything within those parameters would violate code.

 

[DesertHawk]

You must maintain a 3' clearance around your electrical panel, so installing anything within those parameters would violate code.

Ah, got it. Well, scratch that idea. The other place I can mount the heater is on the other side of the house, on the other side of the bathroom wall. This is the side the gas meter is on, which would be nice as I should be able to pull from the main gas line with a very short run of pipe. Water lines will be longer to the kitchen, but the shower should heat up almost immediately.

 

[DesertHawk]

You must maintain a 3' clearance around your electrical panel, so installing anything within those parameters would violate code.

I found this, which states there must be 30" of working space around the electrical panel. Assuming there is enough space remaining to the right of the main panel to meet that 30" requirement, would it be possible to mount the heater to the left of the panel and still comply with the code?

2015 IFC
605.3 Working space and clearance. A working space of not less than 30 inches (762 mm) in width, 36
inches (914 mm) in depth and 78 inches (1981 mm) in height shall be provided in front of electrical
service equipment. Where the electrical service equipment is wider than 30 inches (762 mm), the
working space shall be not less than the width of the equipment.

 

[Oso954]

Assuming there is enough space remaining to the right of the main panel to meet that 30" requirement, would it be possible to mount the heater to the left of the panel and still comply with the code?

Yes, it would meet code minimum.

 

[chandler48]

IF, as you say the space is to the RIGHT of the panel, then it would seem mounting it to the LEFT of the panel would disrupt all the ions in the world? We'd need to know how much space is to the LEFT.

 

[DesertHawk]

Here's the general idea. I took measurements, and I can fit the heater (which is approximately 18" wide) between the open window and the main panel while both respecting the 12" minimum clearance from the window and allowing 30" of working space around the panel. See the measurements in the diagram.

And in fact, codes for tankless heaters specify that the exhaust port must be 12" from an open window, not necessarily the body of the heater itself. The heater I selected is an A.O. Smith GT15-240, which has its exhaust in the center of the unit. So I actually have a little bit of wiggle room side-to-side.

Assuming I'm meeting all necessary codes, this may work.

 

[chandler48]

You have the clear distances marked on your photo, BUT the tankless would have to be mounted OUTSIDE that 30" parameter, not inside it.

 

[TarheelTerp]

I am in the process of installing a natural gas-powered outside tankless water heater. ... I guess the code by which I should abide is for 3/4" gas lines ... It's a small house, so...

Is that 3/4" enough BTU capacity?
Why do you feel you need more than a standard WH (wherever it's installed)?

 

[DesertHawk]

You have the clear distances marked on your photo, BUT the tankless would have to be mounted OUTSIDE that 30" parameter, not inside it.

The electrical codes I found said the electrical panel must be located somewhere within a 30" boundary (left to right). It doesn't specify actual clearances away from the meter, only that it must reside within a 30" area. I can meet that requirement and still keep the water heater 12" away from the window to the left. Assuming this is being interpreted correctly, of course.

 

[DesertHawk]

Is that 3/4" enough BTU capacity?
Why do you feel you need more than a standard WH (wherever it's installed)?

The issue has more to do with space inside the house rather than hot water capacity. It's a very small house, and every square foot counts. By getting rid of the water heater inside and installing the tankless unit outdoors, that frees up a nice bit of space off the kitchen.

 

[chandler48]

The meter is a moot point. The clearances you are reading about are to be to the right, left and in front of the panel.

 

[DesertHawk]

The meter is a moot point. The clearances you are reading about are to be to the right, left and in front of the panel.

I believe you are referring to the depth of the working space. From what I understand, the electrical equipment can be located anywhere within the 30" working space, as long as it is indeed within that space. See attached diagram.

This comes from electrical code. Are you referring to gas/plumbing code?

 

[stiksandstones]

What did you end up doing?? I've got a similar situation brewing-not quite as tight as yours, but....

California-Outdoor tankless mounting specs question

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