Are you sure it doesn't call for more than one circuit? I have wired one that took 3 single phase 40 amp circuits
Ya....I had a service call that felt with a whole house instant hot..it was being fed with (3) 240 volt 40 amp breakers....(3) 8/2 cables went to it :huh: could not believe it until I saw the paperwork with it.
(F) Electric Heating Appliances Employing Resistance-
Type Heating Elements Rated More Than 48 Amperes.
(1) Electric Heating Appliances. Electric heating appliances
employing resistance-type heating elements rated
more than 48 amperes, other than household appliances
with surface heating elements covered by 422.11(B), and
commercial-type heating appliances covered by 422.11(D),
shall have the heating elements subdivided. Each subdivided
load shall not exceed 48 amperes and shall be protected
at not more than 60 amperes.
These supplementary overcurrent protective devices
shall be (1) factory-installed within or on the heater enclosure
or provided as a separate assembly by the heater
manufacturer; (2) accessible; and (3) suitable for branchcircuit
protection.
The main conductors supplying these overcurrent protective
devices shall be considered branch-circuit conductors.
You are limited to max 60A per circuit but get to run more than one circuit to the water heater.I also thought we were limited to 60 amps thru 422.11(F)
You are limited to max 60A per circuit but get to run more than one circuit to the water heater.
I was talking to a friend over the phone who was asking about the wire size. I asked a few times to confirm there was only one circuit and he states there is only one, this is a commercial application.
I also thought we were limited to 60 amps thru 422.11(F)
Ya....I had a service call that felt with a whole house instant hot..it was being fed with (3) 240 volt 40 amp breakers....(3) 8/2 cables went to it :huh: could not believe it until I saw the paperwork with it.
422.11(F)(3)
Not exceeding 120 amps
And protected not over 150 amp
.............&........
Why is it hard to believe? No way a 4500 watt element that is typical in storage type water heater can raise water temp instantaneously as it is used, unless it is fairly warm to begin with. The size of these units will vary some depending on incoming water temp, some places you may have to raise it 75 to 80 deg F, that either takes time in a tank type heater or a lot of energy nearly instantaneously in a tankless heater.
And there was no suplimentary ocpd on the unit.....? (3) 8/2 went straight to the heater, I had to go down stairs to turn it off.