Electric Water Heater Element replacement

[Twowaxhack]

Don't confuse the ampacity of 12-gauge Romex wire, 20 amps, with 12-gauge copper wire that has higher rated insulation, 25 and 30 amps. Appliance manufacturers do not use Romex for internal wiring.

I found a 50 gal electric with 4500w elements running on old 12ga cloth covered romex a few months ago.

It had been working for years. The wire was approximately 25’ from the service panel.

I didn’t leave it that way but it was infact working.

I installed 3800w elements in the new heater, removing the 4500w factory elements. I replaced the 50 with a 40.

 

[RetiredInFl]

Why do you want the higher wattage ? Just for faster recovery ?

Of course.

 

[RetiredInFl]

Remember the original conversation was using 5500W elements in a manufactured 3800W unit.

Actually it was initially for swapping 3800->4500 if you are referring to MY op. I just ordered 2 OEM AO Smith 4500 watt elements off eBay for $9 each and will stick with that. Was tempted to go 5500 but it’s not really necessary for our use. Actually 3800 would really have been fine but I like long hot showers !!

 

[MicEd69]

I found a 50 gal electric with 4500w elements running on old 12ga cloth covered romex a few months ago.

It had been working for years. The wire was approximately 25’ from the service panel.

I didn’t leave it that way but it was infact working.

I installed 3800w elements in the new heater, removing the 4500w factory elements. I replaced the 50 with a 40.

Yep, you find all kinds of wiring issues in older homes that aren't just up to code but are dangerous and an accident waiting to happen. 12 gauge wire on a 50 amp breaker, WOW!

I assume you also changed the wiring out to 8 gauge after replacing the 50 amp breaker to 40?

 

[sarg]

Replaced a 50 gallon with a 40 gallon unit

 

[MicEd69]

Replaced a 50 gallon with a 40 gallon unit

Well, that's what I thought at my first reading. But as this thread is about the size of heating elements, and the gallonage of the water heater has no bearing on the power going to each of the heating elements, I thought Twowaxhack meant the size of the breaker. And as the water heater with 4500W can draw 37 to 41 amps, a 50-amp breaker would be appropriate for the amperage, but DEFINITELY not the wire size.

 

[Twowaxhack]

Well, that's what I thought at my first reading. But as this thread is about the size of heating elements, and the gallonage of the water heater has no bearing on the power going to each of the heating elements, I thought Twowaxhack meant the size of the breaker. And as the water heater with 4500W can draw 37 to 41 amps, a 50-amp breaker would be appropriate for the amperage, but DEFINITELY not the wire size.

A 4500w element @240v runs about 18-19 amps on your test meter

 

[Twowaxhack]

Makes you wonder if Rheem uses heavier insulation on the 12ga wire used in their 5500 units because the standard 12ga wire is rated for 20 amps and the 5500w elements could draw 23 amps ( with the mandated safety factor the requirement would be just under 29 amps. )
RetiredinFl = I would not "push my luck" ..... never been a fan of electrical fires.

You were/are correct. @sarg

Rheem tech support confirmed their 5500w element heaters use 10ga internal wiring.

I was wrong, very rare
Mine is still operating for now, I’m going to leave it. I wouldn’t do it for a customer.

 

[MicEd69]

A 4500w element @240v runs about 18-19 amps on your test meter

Doesn't an electric water heater have 2 elements? Two 4500w elements @240v runs about 37 amps and at 220v about 41 amps. Or does a water heater only use one element at a time?

 

[Twowaxhack]

Doesn't an electric water heater have 2 elements? Two 4500w elements @240v runs about 37 amps and at 220v about 41 amps. Or does a water heater only use one element at a time?

Standard configuration operate non simultaneously

 

[sarg]

The top element turns on first to start the warming process. Once the water in the top half of the tank reaches the set temperature, the top element turns off, and the bottom element turns on to heat the rest of the water.

 

[MicEd69]

Standard configuration operate non simultaneously

Understood. I've always had and installed natural gas water heaters. Thanks for educating me on electrics.

 

[Twowaxhack]

Understood. I've always had and installed natural gas water heaters. Thanks for educating me on electrics.

Best water heaters made is your basic electric.

Every hardware store in the country has the parts.

In a pinch you can wire the element straight to a power source bypassing either thermostat.

You can install 120v element and wire it straight to a common receptacle

Many tricks.

You can link two together and have it operate on one 30amp feed.

 

[MicEd69]

But I can take a warm shower when I lose electricity with a gas water heater. And one gets pretty sweaty BBQing all the meat you had in your freezer when you lose power as well. LOL!

 

[Twowaxhack]

But I can take a warm shower when I lose electricity with a gas water heater. And one gets pretty sweaty BBQing all the meat you had in your freezer when you lose power as well. LOL!

Standby generator solves that. And some gas heaters use 110 to power the controls up.

If a gas water heater control goes out it’s usually a 3 day wait unless you want to pay even more for it. Some controls are $300. And the new ones suck, years ago you might’ve had a good argument.

 

[gagecalman]

You were/are correct. @sarg

Rheem tech support confirmed their 5500w element heaters use 10ga internal wiring.

I was wrong, very rare
Mine is still operating for now, I’m going to leave it. I wouldn’t do it for a customer.

I guess Rheem gave you bad info.
I just installed this Rheem 5500w water heater and it has 12ga wires inside.

 

[Twowaxhack]

I guess Rheem gave you bad info.
I just installed this Rheem 5500w water heater and it has 12ga wires inside.

Doesn’t surprise me. I believed I had seen 12ga in the field on new heaters but it’s been years since I’ve installed a factory 5500w element heater.


Thanks for the clarification and definite answer.

 

[Pipe Dreams]

Thanks, that is what I assumed. Can I push it to 5500 watts? Are they the same length?

is the reason you want higher watts is faster recovery? That is the only thing I can think of..............4500 watts is the standard, I would not try 5500, but the worse that would happen is the wire burn in the heater...........no good.

So anyway, if the issue is recovery, you could install one of those mixing valves so you can bump the water temp up to 140 or so, which will do nothing for recovery, but give more hot (mixed warm) water at the faucet or shower. If you do this, keep an eye on the T&P valve to make sure it does not start to drip......

 

[BlueSkyHigh]

In a pinch you can wire the element straight to a power source bypassing either thermostat.

Reminds me of the time my old Bob Carver designed Phase Linear 700 watt power amplifier was blowing fuses regularly in the right channel. I got upset that our party music was being interrupted so decided to wrap one of the blown fuses in aluminum foil. About a minute and a half later, the voice coil of the 15" woofer in the right channel of Pioneer speaker ejected itself through the grill cloth.

By the way, 12awg wire can support 30 amps if you are willing to make it with insulation such as THWN-2, THHN, XHHW-2, USE-2 that will take temps 90°C (194°F).

 

[TomFOhio]

When I replace a water heater element I never go higher on the wattage. Just a piece of mind for me. I've gone a few amps
lower with no complaints. I don't care what the wire size is.