Has anyone seen those brand new water heaters that are instantaneous and they need 3-40 amp feeds? What do you do about a disconnect within 50' and/or within eyesight?
I suppose they could pull a properly sized feeder and install a small subpanel to an area within sight of the equipment, then run the needed branch circuits to the water heater from there.
One thing though… I know that the SQD QO 6/12 circuit panels I have are only rated at 100A, so not sure if they are available with a higher ampere rating.
If not, then one possible problem might be if the feeder were sized only as needed for the water heater loads but, a larger panel was install installed because of the needed higher ampere rating. Someone else could come along later and run additional circuits out of it to feed other loads.
I'm working on the same thing, in richmond ca, trying to find a small robust panel on opposite side of wall in 1100 sq. ft house, and not have to put in a 20 space panel for 6 slots?
I saw some 6/12s on the SqD site but they are more expensive than a 20/40.
The OCP for the subpanel will prevent the feeder from OL. I seem to remember a GE panel that was 125 amp rated buss.
How about a contactor in a small panel with a push button/switch by the heater?
How about a lock out on the service panel?
If you have a sub panel within sight of the water heater that can be your disconnect.
Is that 3 separate heaters turning ON separate times, or all three turn ON at the same time?
I bet that will dim the lights every time it turns ON. Wouldn't that be annoying? Have you informed the customer on the possibility of the lights dimming?
I agree that if there is a sub panel or service panel within 50/eyesight, then we would meet the code. However the service is in the basement and the house is finished, and they install a new water heater in the laundry room, Now what? Could you accept a lockable breaker(s) for the disconnect? Install a sign on water heater stating that the heater has multiple feeds?
This might be the compelling reason to put the sub panel near the water heater.
I know the code allows lockable breakers, how many homeowners actually understand LOTO procedures or have the proper equipment?
Is there room to install three 40 A solid link disconnects in the laundry room? Could they all be tied together with a piece of all thread so they all operate together?
"All thread" is not a "listed handle tie" so that would be a no.
I wonder if 6 pole pull-outs similar to the the cheapie air conditioner
disconnects are available. If not, it seems it's a ripe time to market something like that.
Economically, does it make sense to use a mechanically held lighting contactor? The idea being that a simple toggle switch would throw six poles.
I remember 20A and 30A rating contactors by SqD.
Is any NEMA player coming out with a sweet solution for this application?
You can't use contactors as disconnects.
Guess a sub-panel with a 'main' and three branch CBs is a way to go.
The lock-out (if needed by placement) could be installed on the 'main'.
(Two pole like may be used on an oven/range)
Oddly, I only came accross one job with this type unit about 2 years ago, the Ec was debating how to do this when I was there for a rough, and that job is still at a standstill ($$$$) Strange thing was the house has a 150 amp service!
I would be interested in the load calc that would allow a 110 a water heater on a 150a service. What kind of range and HVAC equipment do they have?
This is a resi that has an addition, with a service upgrade to 400 amp. The job has been at a standstill for quite some time (1 1/2 to 2 years) due to $$$$. The EC at the time was basically a lost soul with a few items, the WHtr only one of them.
I agree that a sub panel by the water heater would be the best option. However what if there is no room? Say the new water heater is in a closet with no room for a sub panel? Then what?
That is the same problem we have with air handlers. The AHJ has to make up his mind, do we waive 110.26 or the "within sight" rule. I guess that is why we make the big bucks
In NJ we have a form which is a "Variation" to the code. It has 3 parts, (I will paraphrase) 1) What part of the code can't you meet? 2) Why can't you meet the code? 3) How are you going to make up for the problem?
The Homeowner/EC signs it and I would sign it and the Construction offical would sign it. I have the option of accepting or rejecting the EC/HO request. If I accept it, the form goes in the file.
I am not an electrician nor do I know or understand the NEC.
Is it required that all three circuits need to operate simultaneously? Is three independantly operated disconnects suitable as long as there is sufficient labeling indicating that the water heater has multiple sources of power?
The "wink and smile" here is in relaxing the 110.26 violation when you put a disconnect in a closet. Whether they would extend this to a sub panel is questionable. Having a single OCPD in a disconnect box seems OK though.
The other place I see the "readily accessible" violation is when the air handler is hanging from unistrut in the garage ceiling. They generally have the disco up there too. That is great for the servicer but you can't reach it without a ladder.
There seems to be a lot of flexibility in the location of air handler disconnects, even by the same guy who will walk around the condenser disconnect with a yard stick.
The same seems to be true of water heater disconnects. They often show up in closets or in a corner of the garage where 110.26 can't be met, even before the homeowner starts bring in his stuff.
I suppose if I was a code nazi I would insist that the customer had the sub panel or disconnect in the hall outside the closet but still close enough that you could see someone approaching it from the water heater.
Buy a picture to cover it up.