My 120v 40 gal tank is connected by way of a 10/2 wire to the panel and controlled by 30a dbl breaker. Also there is a switch in kitchen to turn off when not needed. Would the switch be a standard 120v switch and would the tank be connected only using 1 leg of wire. Where is the most usual place to disconnect the one leg. I want to go to 240v tank, so would I have to replace or remove switch, thanks.
120v Tank Connected to 30A Dbl Brk
- Thread starter Bruce Dew
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Phog
Active Member
I believe that all hots to a load must be simultaneously switched to meet code (someone can correct me if I'm wrong). Otherwise the load can be unintentionally powered as a result of failure, for example by a short circuit on the switched leg.
In a 120V circuit there is a hot and a neutral, and you only need to switch the hot, so you just use a standard single pole light switch. In a typical single phase 240V circuit there are 2 hots (and no neutral) so you would need a two-pole 30A 240V switch.
Also, if you already have a 2-pole breaker hooked up to the water heater are you sure you have a 120V unit right now? It is of course possible to use only one pole on such a breaker (plus neutral) to get 120V out, and leave pole #2 on the breaker empty. Or you could have a multi-wire branch circuit with some other 120V load on the other pole & shared neutral. But if you presently have both circuit breaker poles hooked up to the water heater via 10/2 Romex then you are hooked up to 240V already.
Please note that I am not an electrician and you need to check code yourself, i recommend consulting with a licensed electrician to make sure you are in compliance.
In a 120V circuit there is a hot and a neutral, and you only need to switch the hot, so you just use a standard single pole light switch. In a typical single phase 240V circuit there are 2 hots (and no neutral) so you would need a two-pole 30A 240V switch.
Also, if you already have a 2-pole breaker hooked up to the water heater are you sure you have a 120V unit right now? It is of course possible to use only one pole on such a breaker (plus neutral) to get 120V out, and leave pole #2 on the breaker empty. Or you could have a multi-wire branch circuit with some other 120V load on the other pole & shared neutral. But if you presently have both circuit breaker poles hooked up to the water heater via 10/2 Romex then you are hooked up to 240V already.
Please note that I am not an electrician and you need to check code yourself, i recommend consulting with a licensed electrician to make sure you are in compliance.
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You might re-read the label. I think a 120 volt 40 gallon electric water heater would be unusual.
WorthFlorida
Clinical Trail 5th session completed 4/24/24.
Reach is right, you have a 240v water heater. The double breaker you have from your description is a single lever for both L1 and L2. The only 120v water heater were for campers and trailer homes. They were usually no more than 10 or 20 gallons under the cabinet type with one heating element and that was a long time ago. From your descriptions about the cutoff switch, you need to call an electrician since you seem to be over your head with this. If you are sure you have 10/2 and not 10/3 then someone hacked it and running the water heater on 120v. If the thermostat wiring of the WH has been changed, 120v will work but a very slow recovery.
Jadnashua
Retired Defense Industry Engineer xxx
Many 240vac devices have no need for a neutral, so a 2-wire cable (plus ground) is more than sufficient to run it. You'd reidentify the white, neutral wire (tape or marker will work) if you want to do it correctly, but that's not always done.
A two-pole switch can be made to look the same as a single pole one, but most of those do not handle 30A (20A is fairly common as is the ability to switch 240vac circuits). If you pull the cover off of the switch, you may be able to tell, and it may have the specs on the front, but on the back is more common, so you'd need to pull it out of the box. Best to remove power first, though. A 2-pole switch would likely have 5-connections: L1-L2 in, L1-L2 out, and the safety ground. A simple two-pole switch would have three, L-in/out, and safety ground. Depending on how old the installation is, it may omit the ground wire.
A two-pole switch can be made to look the same as a single pole one, but most of those do not handle 30A (20A is fairly common as is the ability to switch 240vac circuits). If you pull the cover off of the switch, you may be able to tell, and it may have the specs on the front, but on the back is more common, so you'd need to pull it out of the box. Best to remove power first, though. A 2-pole switch would likely have 5-connections: L1-L2 in, L1-L2 out, and the safety ground. A simple two-pole switch would have three, L-in/out, and safety ground. Depending on how old the installation is, it may omit the ground wire.
Not really since I purchased and installed it myselt except connecting the electric, replaced a 30 gal 120 with 40 gal 120.
We're talking some 38 yrs ago when installed; it's a fleetwood manu home.
If the existing switch also has the neutral wire that feeds the water heater in the switch box then it’s possible. You would need to repurpose the current neutral wire as an additional hot leg at the circuit breaker box and mark it as a hot leg with either black tape or black marker. Then remark it at the switch box to use it as a to leg. Replace the single pole switch with a 30 amp double pole switch and wire it correctly. Then do the same with the white wire at the water heater end (mark it Black) and connect it to the 240v WH.
I have a double pole switch on my 240v 30 amp cabin water heater to easily disconnect power when away.
Here’s a picture of mine.
the grey box above the switch is a power company device that allows them to turn power off the heater on high demand hours. It gives me a $6/mo discount in my electric bill.
I have a double pole switch on my 240v 30 amp cabin water heater to easily disconnect power when away.
Here’s a picture of mine.
the grey box above the switch is a power company device that allows them to turn power off the heater on high demand hours. It gives me a $6/mo discount in my electric bill.
Here’s a typical 30a Dobke Pole switch. https://www.amazon.com/Leviton-3032...uble+pole+30+amp+switch&qid=1579323080&sr=8-2
Stuff
Well-Known Member
Code requires a disconnect within site of the water heater or to provide a lockout on the breaker. Normally panel within site in garage/basement so not an issue. Otherwise people miss the requirement. For 240v loads both legs need to be switched so that double pole switch is appropriate. Also can use an air conditioner style disconnect box - easier to retrofit but ugly.
That is the one in my kitchen to shut off hot water heater for vacation or other reasons. So would maybe one leg here not be connected. I still only get 120v to heater and finding new 120v heaters at 40 gal are hard and expensive, like to just change over to 240v.
WorthFlorida
Clinical Trail 5th session completed 4/24/24.
At the heating element connection, place the volt meter across both terminals. It will read 240v or 120v. Does your water heater have one or two heating elements? Can you take a picture of the label on the WH and post it?
Jadnashua
Retired Defense Industry Engineer xxx
Measuring from a hot to neutral or ground reads 120, but from hot to hot, it should read 240. It's all about your reference point.
I have wired storage buildings, subpanels, and many other electrical devices so I know what a 120v hot water heater is. Why u folks keep trying to tell me it's 240v is beyond me. Guess I will just do it the hard way and pull panel cover. Thought it would be simple answer with provided facts.
Now I think I know where it's reduced, at the tank, by not connecting 2nd hot leg it's only getting 120 so if I connect both legs I should get 240 which is why it was made that way by Fleetwood; to give consumers option of running bigger tank with 240 or staying small with 120.
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WorthFlorida
Clinical Trail 5th session completed 4/24/24.
Sorry Bruce if all of us who have responded doubting this unit. I was asking for a picture of the WH label as a learning curve. No one seems to have ever come across a 120v 40 gallon WH, other than a point of use unit which may be no more than a few gallons. We all learn from each other from those who post questions and those that try to give their best suggestion. I never heard of Fleetwood Homes but I had a feeling is a pre fab home. After looking it up there is a dealer in Christmas, FL, only a few mile from me, and I've seen the entrance and sales office.
Have done more research and find the 10/3 connected as such; white wire to heater and black wire with wire nut on it (no connection), ground is grounded, so apparently the 240 is being terminated by capping the black wire (am I correct). If this is the case I only need buy 240 tank and connect using both wires, right. Have a clamp tool but not sure how to use on the wires, I assume place around each colored wire and get readings. Let me know what u think, thanks.
Spoke to soon, the blk is connected to blk from heater and grd to grd. So now I still don't know how much voltage I have in the wire but heater is definitely 120 with 1 element. Put clamp around each wire but got no reading above 0. I'm stumped!
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Jadnashua
Retired Defense Industry Engineer xxx
What's connected at the panel? When you use a cable and aren't using the wire color conventions, you are supposed to mark them. If the white wire was hot, it should be either wrapped or marked with an appropriate color.
If they twisted the wires, you should be able to remove the wire nut to measure, but be careful.
What meter are you using?
If they twisted the wires, you should be able to remove the wire nut to measure, but be careful.
What meter are you using?
WorthFlorida
Clinical Trail 5th session completed 4/24/24.
Turn up the temperature at the thermostat to put power to the heating element and be sure the clamp meter is in AMP mode.
The clamps don't measure voltage. You need a pair of test leads to measure voltage. The meter with the clamp-around ammeter will normally also measure voltage, but you need to select AC voltage, and use the probes.
It may well be that you can put the wire nut onto the white wire, and use the capped black for the other hot. You refer to a black wire and a white wire. What color is the third wire-- red?
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