On Saturday, December 15, 2018 at 1:13:47 AM UTC-5, danny burstein wrote:
In Clare Snyder writes:

[snip]

Your only option is a 1500 watt.

Section 422-14 of the National Electric Code reads:

b) Storage type water heaters. All fixed storage type water heaters
having a capacity of 120 gallons or less shall have a branch
circuit rating NOT LESS THAN 125 percent of the nameplate rating of
the water heater.

Just as a related explanation: In general, if you're using
a "continuous load", that is, one that'll stay at maximum
rating for over (ummmmm.... 15? minutes at a clip?), you're
supposed to de-rate the ampacity (current carrying rating)
of the wiring.

Continuous is defined in the code as an expected load over 3 hours.
If the code didn't address water heaters separately and essentially
treat his 20 gal WH as a continuous load, I would argue that it isn't
a continuous load at all. I guess the issue could be that someone
could leave the hot water faucet open, running, which would make it
into a continuous load. But when talking about continuous the code
says "expected", which leaves it open to interpretation. But the WH
is covered separately, so it doesn't matter.






Reason is that the rating is based in large part on
the heating the wiring goes through.


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