Hot water heater - temporary generator setup?

[Dusty Floor]

We're in the after-effects of "SnowTober" here in Western CT, and may be another week without utilities. We have a 7kW generator, and a professionally installed transfer panel, so we're pretty well set (fridge, freezer, furnace, well, a few lights, and outlets for charging, etc.). The major exception is warm water. Our HWH is listed as 4500/3380 Watts (208/240v), so the generator could support it (with no other load) for an hour or so each day for a quick shower. I'm thinking I could make up a cord hardwired to the unit, with a plug matching the 240v outlet on the generator and swap it in instead of the feed to the transfer switch as needed.
Is there anything really bad about this plan?

PS, I can't add it to the existing transfer panel because it's on a sub-panel at the opposite end of the house.

 

[Charles (in GA)]

No need to do any of this...... you say you are heating hot water......... so.........

Really, it should work fine. Water heater directly connected to the generator................... hmmmmmmmmm ..... does there need to be an earth ground in here somewhere since this is water we are fooling with?

Charles

 

[nehog]

Were this mine, I'd consider a permanent plug and outlet at the water heater, and an extension cord (custom made, 10 AWG) that would reach the generator. Then unplug the water heater from the normal outlet, plug it into the extension, and plug the extension into the generator. Should work fine!

I have a similar problem, except that my water heater has its own meter, so it can't go through the transfer switch... I'm considering doing the same thing, (slightly modified as I don't has the access problem you refer to, everything is nearby for it...)

 

[Dusty Floor]

Thanks.

Charles, I was thinking about the ground issue; the generator being fairly close to the main panel (and not grounded when it's not connected via the usual cable) that I could use a set of automotive jumper cables to ground the generator frame to the ground rod that the main panel is connected to.

Peter, my wife actually suggested the idea of a permanent outlet for "normal" operation that would make it easier to switch back and forth; may do that while I'm at it; then I could just make a 10AWG adapter cable from that plug configuration to the generator cable.
Chip, I thought about a lower wattage element; problem is I have no way to power the HWH and the rest of the house at the same time due to the fact that it's on a remote subpanel (and I don't have capacity in my transfer panel for another circuit, much less a pair for a 240v device), so I might as well heat the water as quickly as possible while it's connected.

-tom

 

[mrb]

instead of a permanant receptacle for the HWH (which likely wouldnt be code) just use a little transfer switch for the water heater and the appropriate inlet.

 

[Highbeam]

Should have just done a whole house interlock instead of the generator subpanel that only takes a few circuits. WOulod have saved you money and also eliminated this water heater issue.

If you backfeed the main panel then the subpanel is also backfed. Yes, it is legal to backfeed the panel if you have an interlock installed. About 150$.

To your question though, yes, you can plug the water heater to the genset. The heater is actually a very good load. Resistance so no surge, and balanced across each "phase" of the 220 so the generator load is even.