Electric water heating

[theoldwizard1]

This is a question mainly for people with a 10 or 12 gallon water heater who frequently use shore power electricity to heat their water.

Most 120V heat elements are about 1500W so they are well less than a 15A draw. Has anyone installed a 2000W element or even a 240V 5500W (2250W @ 120V) element ? Both would require a 30A or 50A shore power connection AND some upgrades to the wiring (at least 12 gauge wire) and breaker inside your RV.

[DownTheAvenue]

Roger10378 wrote:
To change to 240V would be a lot of work as most if not all RV electric panels do not have 240 available. You would have to change to a house panel and then upgrade the wire from the breaker to the water heater

Not correct. EVERY RV with 50 amp service has 240 volts to the electric panel inside the RV.

[Cummins12V98]

pianotuna wrote:
Hi,

I think the intent of using a 240 volt element is to reduce the wattage, and lower the number of over load trips at the shore power breaker.

Cummins12V98 wrote:
30A does not provide 240V only 120.

Understood but what does what you say have to do with my quote?

My point was it's not possible to use 240V element on 30A.

[Rick_Jay]

theoldwizard1,

First of all, no, I have not done what you ask. We've always had plenty of hot water with our 10 gallon water heater, though a few times we did have to run propane AND electric.

Do you have 50A service on your RV? If so, most 50A RV breaker panels WILL HAVE 240VAC available when connected to a properly wired 50A service. You would have to change the breaker in the box to one which connected to both "hots". You might be able to even use the same cable going to the water heater. You obviously would need a 240VAC heating element the current draw of which would have to be within the wire & breaker ratings.

Keep in mind, however, if you do this, your water heater WILL NOT WORK ON ELECTRIC if you have 30A service. 30A service is 120V only. It also may not work off your generator as many generators (even our 7 kW Onan) put out two 120VAC lines, but they are in phase, so 240V is NOT AVAILABLE on generator power. In my opinion, these are two big negatives, and probably why you don't see it done much, if at all.

~Rick

[pianotuna]

Hi,

I think the intent of using a 240 volt element is to reduce the wattage, and lower the number of over load trips at the shore power breaker.

Cummins12V98 wrote:
30A does not provide 240V only 120.

[Cummins12V98]

30A does not provide 240V only 120.

[S_Davis]

You can get up to a 3,000 watt 120 volt element.

[DrewE]

theoldwizard1 wrote:

Most 120V heat elements are about 1500W so they are well less than a 15A draw. Has anyone installed a 2000W element or even a 240V 5500W (2250W @ 120V) element ? Both would require a 30A or 50A shore power connection AND some upgrades to the wiring (at least 12 gauge wire) and breaker inside your RV.

Note that a 5500W 240V element will not be 2250W if powered by 120V, but rather 1125W. Half the voltage means half the current, per Ohm's law, and thus a quarter of the power dissipation.

[cpaulsen]

On my 12 gallon water heater......I just use electric all the time......unless it has been off for some time then I use both propane and electric at the same time.

[wa8yxm]

I went the other way on my Six gallon tank.

I switched the 1500 watt 120 volt element for a 1500 watt 240 watt.
This gives me about 375 watts at 120 volt
YES it takes longer to heat the water

But my trips to the park pedestal when on a 30 amp site due to overload WAY WAY WAY Down.

[ktmrfs]

you could with some work, but if you need recovery, just turn on propane AND electric.

[Roger10378]

To change to 240V would be a lot of work as most if not all RV electric panels do not have 240 available. You would have to change to a house panel and then upgrade the wire from the breaker to the water heater

[pianotuna]

Hi,

I'd rather go down from the 1400 watt. Recovery time is, for me, a non issue. I've used the propane side twice since 2009. I have a ten gallon unit.

From ambient to first cycle takes about 90 minutes. If no water is drawn it appears to cycle every 4 hours and takes 15 minutes of "on" time.

[time2roll]

OK to run on propane at the same time for fastest recovery. (assuming you have propane)
Also there is an RV tankless W/H available for continuous hot water.
I have not replaced the element.

[Old-Biscuit]

Atwood uses a 1400W element......use to use a 1500W but went to 1400W to lower the amp draw
Suburban uses a 1440W element

RV Water Heater electric elements are fed by a 15A CB
As you stated ....Wiring & CB changes would be necessary

So NO....
Doubt anyone has done that as it is not that much of an improvement (cost/benefit)

1400/1440W element have a recovery time of roughly 6.2 gal/hr (based on initial 70*F water temp) ---even shorter time for reheat cycle (from 100*/110*F water temp)
Want faster recovery time.turn electric & propane on at same time (16.2 gal/hr ---70*F water)

Want hot all the time.....leave electric ON