non gmc- 240V water heater in 50 amp Class A

[dave silva]

Sometimes google is no help and you just have ask smart old guys.

Helping a friend convert his water heater in a mid 90s pusher. He wants an electric tankless. Is it possible (and safe) to bring both legs of his
50 amps service to a 240V water heater?

thanks
--
Dave & Ellen Silva

1972 Revcon Olds 455, toro drive train. All Stock

 

[d c *mac* macdonald]

Is he already using a 240 Volt appliance? If so, I would imagine he could
add a new circuit (with dual breaker of appropriate amperage capacity).
That "assumes" of course that there is space on his service panel to add
that breaker and appropriately sized wiring. I suspect a "professional"
electrician would be advisable to do that wiring.

What say our resident electrical experts?

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com

________________________________
From: Gmclist on behalf of dave silva via Gmclist
Sent: Monday, May 18, 2020 13:32
To: gmclist
Cc: dave silva
Subject: [GMCnet] non gmc- 240V water heater in 50 amp Class A

Sometimes google is no help and you just have ask smart old guys.

Helping a friend convert his water heater in a mid 90s pusher. He wants an electric tankless. Is it possible (and safe) to bring both legs of his
50 amps service to a 240V water heater?

thanks
--
Dave & Ellen Silva

1972 Revcon Olds 455, Toro drive train. All Stock

 

[Jim Hupy]

Ah yes, which came first? The chicken or the egg? There is not much
difference in the recovery times of a 240 volt water heater vs a 120 volt
one. But, neither one of them can compare with a good tankless propane
unit, as well as most of the larger tank style propane units.
But if the object is to eliminate propane from his vehicle, there are more
electrical fires in RV's than propane ones. Either one will burn the coach
to the lugnuts.
Jim Hupy
Salem, Oregon

On Mon, May 18, 2020, 11:40 AM D C _Mac_ Macdonald via Gmclist <

> Is he already using a 240 Volt appliance? If so, I would imagine he could
> add a new circuit (with dual breaker of appropriate amperage capacity).
> That "assumes" of course that there is space on his service panel to add
> that breaker and appropriately sized wiring. I suspect a "professional"
> electrician would be advisable to do that wiring.
>
> What say our resident electrical experts?
>
> D C "Mac" Macdonald
> Amateur Radio K2GKK
> Since 30 November '53
> USAF and FAA, Retired
> Member GMCMI & Classics
> Oklahoma City, OK
> "The Money Pit"
> TZE166V101966
> '76 ex-Palm Beach
> k2gkk + hotmail dot com
>
> ________________________________
> From: Gmclist on behalf of dave silva
> via Gmclist
> Sent: Monday, May 18, 2020 13:32
> To: gmclist
> Cc: dave silva
> Subject: [GMCnet] non gmc- 240V water heater in 50 amp Class A
>
> Sometimes google is no help and you just have ask smart old guys.
>
> Helping a friend convert his water heater in a mid 90s pusher. He wants
> an electric tankless. Is it possible (and safe) to bring both legs of his
> 50 amps service to a 240V water heater?
>
> thanks
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, Toro drive train. All Stock
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[richshoop]

Don't do it unless everything from the shore power cord forward is also upgraded. Especially the main electric panel!

>
>
> Sometimes google is no help and you just have ask smart old guys.
>
> Helping a friend convert his water heater in a mid 90s pusher. He wants an electric tankless. Is it possible (and safe) to bring both legs of his
> 50 amps service to a 240V water heater?
>
> thanks
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[richard h staples]

Dave,
You asked " Is it possible (and safe) to bring both legs of his 50 amps service to a 240V water heater?" Assuming he wires it properly (main
panel, breakers, and wires), I'd say yes. However.... Remember, if he is plugged into a non 240v/50A outlet, either a standard 30 amp or 20 amp
outlet, or even a "50 amp" outlet that's wired like the GMC's internal power outlet, then the water heater simply won't work at all. ie: he will have
0 volts across the heater. Sort of limits where you can camp and get hot water. Of course if he has a generator that can supply 240 volts (unlike
the GMC's Onans), and it's wired properly to his electrical panel, then he's good to go.

HTH

Rick Staples

--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien

 

[RF_Burns]

He should also consider that tankless water heaters consume alot of electrical power. Just reading some on-line reviews and it seems 6.5Kw plus is the
minimum to be happy with the hot water temperature/quantity. 50A @ 240V = 12kw so that's just over 1/2 of your available power. The 6.5kw tankless
will be pulling ~30amps on each leg when operating.

So a pusher usually has 2 A/C units which take 20amps to start and near 15 amps to run so that takes to 45 amps (assuming one A/C on each leg). So you
are at your limit right there. Plus you will other loads like fridges, microwaves, coffee maker, electric skillet, hot plate, toaster, RV's power
converter to run 12v and charge the batteries...etc.

Yes I know the tankless will rarely operate, but consider breakfast or dinner. You have the coffee maker going, toaster and microwave running... then
you turn ON the hot water in the kitchen sink, or someone is in the bathroom... suddenly the current jumps by 30 amps and if either leg exceeds 50Amps
by much, the main breaker will trip and everything goes dead... or reverts to inverter.

So consider the ramifications.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[roy keen]

I would only consider 120 volt. 50 amp service isn’t always available in which case if he is connected to a 30 amp source he would have no hot
water.
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[powwerjon]

The HOT tip here is to use a 240 volt 4000w heating element. They are less expensive than the 120V heating elements and will heat somewhat faster and is more durable. It is not that you use 240 vVAC, but it works well with 120 VAC. I don’t under stand the mindset to spend many unnecessary dollars to make a so called improvements. For about $9 your water will heat faster and use less energy. You don’t need to change the world to make it work better.

J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan

>
> I would only consider 120 volt. 50 amp service isn’t always available in which case if he is connected to a 30 amp source he would have no hot
> water.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[adolph santorine]

J.R.

Ohm’s law.

It’s not just a good idea. It’s the law!

It’s a resistor. Turning electricity back into heat (likely where it started).

It’s not taught in school science courses anymore, so the understanding of the effect of the lower voltage is missing.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Manny Transmission

“The Aluminum and Fiberglass Mistress”

|[ ]~~~[][ ][] \
"--OO--[]---O-"

>
> The HOT tip here is to use a 240 volt 4000w heating element. They are less expensive than the 120V heating elements and will heat somewhat faster and is more durable. It is not that you use 240 vVAC, but it works well with 120 VAC. I don’t under stand the mindset to spend many unnecessary dollars to make a so called improvements. For about $9 your water will heat faster and use less energy. You don’t need to change the world to make it work better.
>
> J.R. Wright
> GMC Great Laker MHC
> GMCGL Tech Editor
> GMC Eastern States Charter Member
> GMCMI
> 78 GMC Buskirk 29.5’ Stretch
> 75 GMC Avion (Under Reconstruction)
> Michigan
>
>

>>
>> I would only consider 120 volt. 50 amp service isn’t always available in which case if he is connected to a 30 amp source he would have no hot
>> water.
>> --
>> Roy Keen
>> Minden,NV
>> 76 X Glenbrook
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[roy keen]

120V heating elements and will heat somewhat faster and is more durable. It is not that you use 240 vVAC, but it works well with 120 VAC. I don’t
under stand the mindset to spend many unnecessary dollars to make a so called improvements. For about $9 your water will heat faster and use less
energy. You don’t need to change the world to make it work better.

J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan

>
> I would only consider 120 volt. 50 amp service isn’t always available in which case if he is connected to a 30 amp source he would have no hot
> water.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

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[
[ maybe I’m reading it wrong but he said both legs of a 50 amp supply for a tankless heater in a diesel pusher? As far as a 240 heater for a 6
gallon Heater I agree a 240 is the way to go that is the way I have done it as it is less likely to burn out.

--
Roy Keen
Minden,NV
76 X Glenbrook