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Electric hot water tank - Big Bill - 06-09-2019

Here's a question I don't recall ever seeing: Can a 30G electric hot water tank be set up for use as a stand alone, plug-in appliance- used as a dedicated, point of use tank for a single laundry machine... and still meet code? Tank would have a hose bib on H & C sides- C connected to supply, H connected directly (and only) to the machine hose. Instead of being hard-wired, a 30A "dryer" cord would be plugged into a dedicated receptacle. The receptacle would be controlled by a 24 hr timer.  I know codes vary by location, but was wondering in general...


RE: Electric hot water tank - blackhat - 06-09-2019

No help with code because ours are too different but do you need hot water to wash whatever you are doing?  I'm single and I can't recall the last time I turned my machine to hot or warm. It's an old style top loader but even corral dirt or construction site crud is no problem cold washing.


RE: Electric hot water tank - Robert Adams - 06-10-2019

Not for sure but I don't think there is a code requirement for hot water at a washer and I don't see an issue with your plan. It's not uncommon to see laundry rooms moved and a small water heater put in just for the washer as it's often a pain to get hot water to locations as all piping is under slab. 

        30 gallons is quite a large water heater for a washer. A much smaller one would supply enough water and heat up quicker. But like mentioned we rarely use anything but cold water however when bleaching white stuff hot water is used. My dad used to run the production side of an Aramark plant here and the key to getting clean clothes in that setting is very hot water and better chemicals than we mere mortals can get. Not to mention soft water as well. But they had stretchers to stretch pants back to their proper size.


RE: Electric hot water tank - Roly - 06-10-2019

(06-10-2019, 12:47 AM)Robert Adams Wrote: Not for sure but I don't think there is a code requirement for hot water at a washer and I don't see an issue with your plan. It's not uncommon to see laundry rooms moved and a small water heater put in just for the washer as it's often a pain to get hot water to locations as all piping is under slab. 

        30 gallons is quite a large water heater for a washer. A much smaller one would supply enough water and heat up quicker. But like mentioned we rarely use anything but cold water however when bleaching white stuff hot water is used. My dad used to run the production side of an Aramark plant here and the key to getting clean clothes in that setting is very hot water and better chemicals than we mere mortals can get. Not to mention soft water as well. But they had stretchers to stretch pants back to their proper size.
My only concern is the 30 gal tank falling over.   Suggest a smaller squatter water heater.  I dont know how much hot water would be required for a washer to bring the water up to a recommended temp for the soap. My washer has a setting that mixes hot and cold to get there, only used in the winter.  Roly


RE: Electric hot water tank - TDKPE - 06-10-2019

(06-09-2019, 07:04 PM)Big Bill Wrote: Instead of being hard-wired, a 30A "dryer" cord would be plugged into a dedicated receptacle.

An obsolete (since the 1996 code cycle) 3-wire dryer plug and cord set has a NEMA 10-30P plug, which is 30A, 125/250V, 3-pole, 3-wire, ungrounded (two hots and a neutral), so technically it's not the correct one to use with a 240V only load. 

If you want to stay as close to by-the-numbers as you can, use a NEMA 6-30P plug and 3-wire cord, as it's a 250V, 2-pole, 3-wire, grounded plug.  A "pole" carries current under normal use, which is why the 250V only plug is only 2-pole while still having 3 wires.  Same plug/receptacle used with any large portable single-phase 240V load, like big woodworking machines, and arc welders (normally NEMA 6-50 for welders, though).

Electrically, it almost doesn't matter, especially if the panel is the main panel, where the grounds and neutrals are all bonded.  But if it's a subpanel, the neutral connection is likely to wander away from zero volts to ground, depending on the load on the subpanel.  Unless you land it on the ground bus.  But if someone then plugs a clothes drying into it, it'll be putting current on the equipment grounding part, and that's also not so good (grounds are not intended to carry current except under fault conditions).

Not to be ultra picky, but since you asked the question . . . Winkgrin


RE: Electric hot water tank - Phil Thien - 06-10-2019

Just wondering, why the need to disconnect, they sell timers that are hard-wired?


RE: Electric hot water tank - TDKPE - 06-10-2019

(06-10-2019, 10:08 AM)Phil Thien Wrote: Just wondering, why the need to disconnect, they sell timers that are hard-wired?

Pool pump timer.  240V, with manual on/off override, and designed for high inrush, which is overkill for a resistance element, but no harm in being robust.   Cool


RE: Electric hot water tank - fixtureman - 06-10-2019

When I was installing pharmacy we would put in little 110 volt water heaters under the skinks any where from 5 to 15 gallon.