Water heaters and cord/plug/receptacle disconnect.

[renosteinke]

Yes, it is. Here is how it happens ....

It starts with an old fuse box, one that has 4-Edison base fuses and two sets of NON fuses. One set of the NON fuses is the main disconnect, and uses 60-amp fuses (largest value made). The other side was usually wired for a range, and had 40-amp fuses with #10 wire. (I seem to recall an understanding that allowed this for range loads, since they were so intermittent).

The trouble is, this is the only 240-volt circuit in the panel. So, years go by, and the first thing that happens is that they need 240 for that new-fangled 'must have' appliance, the clothes dryer. Now they've got a 30-amp appliance 'protected' by those 40-amp fuses. Still, since folks seldom cook and do laundry at the same time, it "works."

Then they decide to replace the gas water heater with an electric one - perhaps because the gas line has rusted through. Where to get 240? From that same circuit. They start blowing fuses, and after about the third trip to the hardware store (or first call to the rental agent), the 40-amp fuses get replaced by 60-amp ones. They'd use bigger ones if they could find them.

All these 'additions' invariable get spliced into the wires, usually at the point closest to the attic entrance. Naturally, there's never enough 'extra' wire to bother with using a box. The splices are usually made by skinning some insulation off the wires and wrapping some stranded wires (from a cheap extension cord) around the old K&T, then wrapping it all with tape. Then some new insulation is piled atop all of it.

The problem isn't K&T. The problem isn't "Edison base" fuses (or any sort of fuses). IMO, compared to the flying, loose splices, fused circuits, and under-protected appliances, the use of the cord material is a fairly minor risk.

 

[kwired]

Yes, it is. Here is how it happens ....

It starts with an old fuse box, one that has 4-Edison base fuses and two sets of NON fuses. One set of the NON fuses is the main disconnect, and uses 60-amp fuses (largest value made). The other side was usually wired for a range, and had 40-amp fuses with #10 wire. (I seem to recall an understanding that allowed this for range loads, since they were so intermittent).

The trouble is, this is the only 240-volt circuit in the panel. So, years go by, and the first thing that happens is that they need 240 for that new-fangled 'must have' appliance, the clothes dryer. Now they've got a 30-amp appliance 'protected' by those 40-amp fuses. Still, since folks seldom cook and do laundry at the same time, it "works."

Then they decide to replace the gas water heater with an electric one - perhaps because the gas line has rusted through. Where to get 240? From that same circuit. They start blowing fuses, and after about the third trip to the hardware store (or first call to the rental agent), the 40-amp fuses get replaced by 60-amp ones. They'd use bigger ones if they could find them.

All these 'additions' invariable get spliced into the wires, usually at the point closest to the attic entrance. Naturally, there's never enough 'extra' wire to bother with using a box. The splices are usually made by skinning some insulation off the wires and wrapping some stranded wires (from a cheap extension cord) around the old K&T, then wrapping it all with tape. Then some new insulation is piled atop all of it.

The problem isn't K&T. The problem isn't "Edison base" fuses (or any sort of fuses). IMO, compared to the flying, loose splices, fused circuits, and under-protected appliances, the use of the cord material is a fairly minor risk.

I will not disagree with what you say here and have seen some of the things mentioned.

My question is what does any of that have to do with supplying a water heater with a cord and plug as mentioned in the OP?

 

[George Stolz]

UL has taken the position that dishwashers and water heaters can be cord-connected only using factory-approved cord sets that were evaluated with the unit. With water heaters they even go a step further, making clear that they will only list such units with cords if they are 5 gallons or smaller and draw less than 15 amps.

What is your source on that? I couldn't find anything like that in the White Book.

 

[jumper]

What is your source on that? I couldn't find anything like that in the White Book.

I found this:

http://www.iaei.org/magazine/depart...ted-water-heaters-be-cord-and-plug-connected/

 

[Dennis Alwon]

I found this:

http://www.iaei.org/magazine/depart...ted-water-heaters-be-cord-and-plug-connected/

Derek, you are full of surprises. Thank you. I have never wired a water heater or furnace with cord & plug but I have heard of some that do. It is good to have something to fall back on.

 

[George Stolz]

I found this:

http://www.iaei.org/magazine/depart...ted-water-heaters-be-cord-and-plug-connected/

Thanks - but again, where does it say this? UL 174? 'Cause it doesn't say it in the White Book.

 

[jumper]

Thanks - but again, where does it say this? UL 174? 'Cause it doesn't say it in the White Book.

I can only go by this from the white book:

These water heaters are intended for household use and permanent connection to the supply source in accordance with ANSI/NFPA 70, "National Electrical Code."

The Table of Contents for UL 174 lists cord connections; however, maybe manufacturers of WH larger than 5 gallons and 120V do not have them tested on this aspect. IDK.

The article only said that small cord connected 5 gallon or less household WH have been listed, not that others couldn't. As I said, maybe no manufactures have had regular WH tested with a cord connection or the small ones have a different UL listing. Again: IDK.

One thought comes to mind, unlike most appliances- especially ones above 120V such as a dryer or range- a WH has no way to turn off the elements on the unit itself. Many times after a person works on one, the reconnection would be under a full load.

 

[George Stolz]

I can only go by this from the white book:

These water heaters are intended for household use and permanent connection to the supply source in accordance with ANSI/NFPA 70, "National Electrical Code."

Yeah, I saw that too, but was given a moment of pause by the first sentence of KSDT:

This category covers storage tank water heaters rated 600 V or less and 12 kW or less and having a tank capacity of more than one gal and not more than 120 gals.

That didn't jive with the five gallon comments floating around - so I wasn't immediately convinced that the "permanent connection" referred to was the NEC version of the term.

The Table of Contents for UL 174 lists cord connections; however, maybe manufacturers of WH larger than 5 gallons and 120V do not have them tested on this aspect. IDK.

I betcha it's in there somewhere, looking at the table of contents. Thanks for that link, BTW.

One thought comes to mind, unlike most appliances- especially ones above 120V such as a dryer or range- a WH has no way to turn off the elements on the unit itself. Many times after a person works on one, the reconnection would be under a full load.

I'm not quite following you there.

 

[kwired]

One thought comes to mind, unlike most appliances- especially ones above 120V such as a dryer or range- a WH has no way to turn off the elements on the unit itself. Many times after a person works on one, the reconnection would be under a full load.

I'm not quite following you there.

If a water heater is connected with cord and plug it will be under load when plugging it in. Only exception would be if the water in the tank is up to temperature already.There is no unit switch to turn if off unless you would install it in the field.

 

[jumper]

One thought comes to mind, unlike most appliances- especially ones above 120V such as a dryer or range- a WH has no way to turn off the elements on the unit itself. Many times after a person works on one, the reconnection would be under a full load.

I'm not quite following you there.

It was merely a passing thought. I can plug in a range or dryer without it being under load using the controls on the unit itself; however a WH has no such controls. If you turn down down the T-stats, it is a guess whether the the elements will energize upon insertion of the plug.

I suppose it may be considered no different than inserting the pull out handle into a unfused disco.

I can only say that as far as I know, cord connections for a regular electric WH are not allowed as none seem to be listed.

Sorry kwired, I was typing when you posted.

 

[kwired]

If I disregard what says about using cord and plug vs hard wiring - I still never can figure the logic of wanting to connect a water heater with a cord and plug - or often just about any equipment that remains in a fixed place in normal use. The driving force behind this logic like many other things is that it will cost less.

If you have typical 4500 watt water heater I can provide a pull out disconnect and 3 feet of flex for about the cost of a cord cap alone. It will take me more labor to assemble the cord cap and receptacle than it will take to put in one disconnect and a piece of flex. I see no cost advantage (Remember the proper plug and receptacle should be a 6-30 configuration and not a 10-30 which typically cost much less than a 6-30).

Same applies to a 120 volt water heater with a 5-15 plug and receptacle. If you use a cheap residential grade 5-15 plug and receptacle chances are a connection will eventually loosen up enough that the cord and plug will experience melt down at some time. Use a good quality plug and receptacle or even a 5-20 and materials cost is high enough you were just as well or even better off to use hard wiring methods - like a switch and piece of flex.

 

[LarryFine]

I still never can figure the logic of wanting to connect a water heater with a cord and plug - or often just about any equipment that remains in a fixed place in normal use.

Like a range or clothes dryer?

 

[kwired]

Like a range or clothes dryer?

Ranges and clothes dryers are at least something that is often removed when owners/tenants change. A water heater usually stays in place until its useful life has passed. Built in cooktops or ovens are typically hard wired - but they are not necessarily going to be replaced or moved as often as a freestanding range will.

 

[renosteinke]

We've got a bit off track, but it's a tangent worth discussing: Design choices- and code limitations on them.

Why put a cord and plug on a water heater? Well, I can think of two good reasons (and one might even still be legal):

First off, water heaters are replaced by plumbers. If I had my druthers, every water heater wuold use a cord and plug, for the simple reason that the plumber is neither trained nor equipped to do electric work. I just want him to unplug the thing ... I might even be persuaded that the same situation could exist with air conditioners. Maybe.

Let's not forget GAS powered heaters either. Modern ones have electric igniters, rather than pilot lights. Commercial ones have flue dampers, oxygen sensors, and all sorts of electrical controls. I think these units even come with the cords supplied by the factory.

I'd certainly rather see a cord & plug than the usual length of Romex, dropping through a hole in the ceiling, and connecting directly to the water heater.

 

[mikeames]

Let's not forget GAS powered heaters either. Modern ones have electric igniters, rather than pilot lights. Commercial ones have flue dampers, oxygen sensors, and all sorts of electrical controls. I think these units even come with the cords supplied by the factory.

I am glad someone mentioned it. Thats what I thought the the OP was about. Then I realized some actually put 30a electric water heaters on cords. WOW learn something new every day.

 

[kwired]

We've got a bit off track, but it's a tangent worth discussing: Design choices- and code limitations on them.

Why put a cord and plug on a water heater? Well, I can think of two good reasons (and one might even still be legal):

First off, water heaters are replaced by plumbers. If I had my druthers, every water heater wuold use a cord and plug, for the simple reason that the plumber is neither trained nor equipped to do electric work. I just want him to unplug the thing ... I might even be persuaded that the same situation could exist with air conditioners. Maybe.

Let's not forget GAS powered heaters either. Modern ones have electric igniters, rather than pilot lights. Commercial ones have flue dampers, oxygen sensors, and all sorts of electrical controls. I think these units even come with the cords supplied by the factory.

I'd certainly rather see a cord & plug than the usual length of Romex, dropping through a hole in the ceiling, and connecting directly to the water heater.

Only problem with that logic is what equipment should be allowed and what shouldn't. You can argue that just about anything will be installed or replaced by a non electrician. Heck even permanent feeders or branch circuits are installed by non electricians all the time.

The plumber replacing a water heater is a different situation and does not happen as frequently as a homeowner replacing a range, or dryer. Some houses will see dozens of ranges or dryers in the same time that only one water heater was in use.

Same goes for HVAC equipment, non portable lighting, water well pumps, booster pumps. Sewage pumps tend to need serviced/replaced more often. I don't really know what to think about dishwashers and disposers, you typically have a choice with them, but I am not sure that I have an opinion on which way is better, both ways have advantages and disadvantages.

 

[George Stolz]

Some houses will see dozens of ranges or dryers in the same time that only one water heater was in use.

I don't know about all that - my house is on it's second water heater, still the same range and (used) dryer. For the record, I've never cord connected a water heater, but had a temptation back in '02 because it would have been a lot less work in that 24-plex. We ended up installing disconnects.

 

[Jim W in Tampa]

Unless you have bad water a normal water heater will last 10 or even 20 years. Elements might need changed more often but not the heater. Washers and dryers at my place never last 10 years, i am happy to get 5. So yes they need a cord and plug.

 

[kwired]

Unless you have bad water a normal water heater will last 10 or even 20 years. Elements might need changed more often but not the heater. Washers and dryers at my place never last 10 years, i am happy to get 5. So yes they need a cord and plug.

Very little to go wrong that is not easy and relatively inexpensive to fix on an electric water heater. Only real need to replace entire unit is if tank goes bad or for change in capacity of unit. Tank full of sediment may warrant replacement depends on how easily the sediment can be removed. I have flushed many out that are only up to lower element without too much trouble.

 

[Strife]

Well, this is exactly what this is (or was, as I changed it already). A small under counter WH with less than 15A load (to touch the other post referring to the UL)

MOST water heaters simply are not listed for cord & plug connection...........check it! Some small, undercounter storage types are provided with cords from the factory, but those are all I have seen. There might be some insta-hot-type heaters that are cord and plug equipped, but I can't remember seeing any lately (past 5 years anyway).