40 Gallon Hot Water Heater Issue

[ehbaseball025]

Im wiring a new hot water heater with existing wires 2 sets of 10/2 wires

Previous Hot water Heater was demoed by plumber, I asked if the whites were spliced together and blacks spliced together when he demoed because its odd to have 2 sets of wires at the hot water heater and he didn't remember.

I wired the hot water heater 2 blacks to black from HWH, and 2 whites to red from HWH, turned the breaker on and it blew up. I thought there wouldn't be an issue as it was working before.

looked at the 2 pole breaker and saw 2 whites lined on the breaker no blacks.

There's continuity between the red and black from hot water heater from the factory

Why would there be 2 sets of 10/2 and the whites only on the 2 pole breaker? Im very confused

I still need to investigate more tomorrow.

 

[Eddie702]

One cable is usually the 240-volt power. The other cable usually is switched through the electric meter to control peak and off peak usage although most areas don't use it any longer (at least in my area).

So 1 cable should have 240 between black & white. The other black and white is just a switch.

If you look in the WH manual it should show the hook up. If you only have 2 wires coming out of the wh you just hook those up to 240 volt. 1 cabel probably goes to the panel and the other goes to the electric meter.

 

[retirede]

You may have also damaged the switch.

 

[kwired]

One cable is usually the 240-volt power. The other cable usually is switched through the electric meter to control peak and off peak usage although most areas don't use it any longer (at least in my area).

So 1 cable should have 240 between black & white. The other black and white is just a switch.

If you look in the WH manual it should show the hook up. If you only have 2 wires coming out of the wh you just hook those up to 240 volt. 1 cabel probably goes to the panel and the other goes to the electric meter.

Makes some sense if both cables ran to the panel - OP said there was 2 whites on the breaker. But with that arrangement what powers the logic circuitry of the controller?

 

[Hv&Lv]

Im wiring a new hot water heater with existing wires 2 sets of 10/2 wires

Previous Hot water Heater was demoed by plumber, I asked if the whites were spliced together and blacks spliced together when he demoed because its odd to have 2 sets of wires at the hot water heater and he didn't remember.

I wired the hot water heater 2 blacks to black from HWH, and 2 whites to red from HWH, turned the breaker on and it blew up. I thought there wouldn't be an issue as it was working before.

looked at the 2 pole breaker and saw 2 whites lined on the breaker no blacks.

There's continuity between the red and black from hot water heater from the factory

Why would there be 2 sets of 10/2 and the whites only on the 2 pole breaker? Im very confused

I still need to investigate more tomorrow.

Possibly.
And I’m kinda going off kwireds post above..

You say two whites went to the water heater from the breaker to power it, but there are two whites and two blacks at the water heater.

In my head I see one white going to the water heater thermostat.
I see the other white tied to black with wirenut.
That black goes to the load control switch(?), then comes back on black to the water heater.

So the water heater would have a white and a black connected to the thermostats.

Clear as mud?

 

[kwired]

Possibly.
And I’m kinda going off kwireds post above..

You say two whites went to the water heater from the breaker to power it, but there are two whites and two blacks at the water heater.

In my head I see one white going to the water heater thermostat.
I see the other white tied to black with wirenut.
That black goes to the load control switch(?), then comes back on black to the water heater.

So the water heater would have a white and a black connected to the thermostats.

Clear as mud?

Most these water heaters don't have space for all those conductors in their termination housing either. Had to be pretty packed in there if that is what was done.

 

[Hv&Lv]

Most these water heaters don't have space for all those conductors in their termination housing either. Had to be pretty packed in there if that is what was done.

Agreed
Especially if it was #10 solid.
Had to used a hammer to get them all in there.

 

[ptonsparky]

Agreed
Especially if it was #10 solid.
Had to used a hammer to get them all in there.

I liked the rubber handles best.

 

[ptonsparky]

Big clue should have been ‘parallel 10s, wth?’

 

[Dennis Alwon]

I wonder if there is a switch somewhere that shuts off one leg. Thus the second cable is a switch loop.

 

[Hv&Lv]

I wonder if there is a switch somewhere that shuts off one leg. Thus the second cable is a switch loop.

What I was thinking in post 5 with the POCO load control.
But..

Maybe a timer switch somewhere in the house?

 

[acrwc10]

Imagine if they came with a wiring diagram or had one on line, just saying.

 

[acrwc10]

looks like you created a dead short by by passing the lower heating element.

 

[GoldDigger]

In places where a lower off-peak metered rate is available for water heating, I think that the most common practice is to wire the normal meter to the upper element, so that hot water is always available, while the metered feed goes to the second element, so that the full tank is only heated during off hours.
I am not sure how this is combined with the normal interlock that enables the bottom element only after the top thermostat is satisfied.
The description of the second pair as a switch leg does not make a lot of sense given that the off-peak usage had to be fed by a second POCO meter which included a time of day switch.

 

[Hv&Lv]

In places where a lower off-peak metered rate is available for water heating, I think that the most common practice is to wire the normal meter to the upper element, so that hot water is always available, while the metered feed goes to the second element, so that the full tank is only heated during off hours.
I am not sure how this is combined with the normal interlock that enables the bottom element only after the top thermostat is satisfied.
The description of the second pair as a switch leg does not make a lot of sense given that the off-peak usage had to be fed by a second POCO meter which included a time of day switch.

We never use (or used)a second meter. No one around this area (NC) did that I knew of.
We simply gave a credit and hoped the switch was working. Trashed that program because so many would take the switch out of the loop to get the $2 credit, or they would cause issues during peak times and we had to send an after hours person to fix something.
It was costing us more than it was saving.
Now we run CVR and put everyone on load control. Saves our peak, saves them money.

 

[tortuga]

Do both 10/2's go back to the panel to separate breakers?
If so thats a modified waterheater for simultaneous use, they take a standard water heater and wire a 10/2 each to element (via a thermostat).
Its used in places with high demand for hot water restaurants, hair salons, dorms etc.

 

[Eddie702]

In places where a lower off-peak metered rate is available for water heating, I think that the most common practice is to wire the normal meter to the upper element, so that hot water is always available, while the metered feed goes to the second element, so that the full tank is only heated during off hours.
I am not sure how this is combined with the normal interlock that enables the bottom element only after the top thermostat is satisfied.
The description of the second pair as a switch leg does not make a lot of sense given that the off-peak usage had to be fed by a second POCO meter which included a time of day switch.

That is exactly how it used to be done around here although most pocos here have given up on the switch in the meter. (they have to all be reset after a power loss) so they they either don't offer two rate tiers or they use a radio controlled switch.

But the install is the same usually a two wire from the panel to the wh for power and a 2 wire from the wh to the meter or switch.

It can be done with a 3 wire as well

 

[mtnelect]

The SCE came out today, to replace the HVAC "Black Box" with an updated box in preparation for summer. I get $50.00 each month off my bill. The box disconnects the condensing unit when required, but not more than one hour per day. For safety reasons, I can override it by pressing a button.

 

[tthh]

The SCE came out today, to replace the HVAC "Black Box" with an updated box in preparation for summer. I get $50.00 each month off my bill. The box disconnects the condensing unit when required, but not more than one hour per day. For safety reasons, I can override it by pressing a button.

That's nice. This house I bought has them and the credit is once a year $70 and no override. Now they only cut them twice maybe three times last summer.

 

[kwired]

Irrigation customers here have load control options. I don't know all the details but for most part they get lower rates the more control they subscribe for. There are some that don't want any control and probably do pay a higher rate because of it.

If you bypass their radio controller, their metering system can let them know you are using when you should be shut down. Or at very least sends out a technician should the radio controller happen to be not working.