You can go to any big box and buy a heater for around $800 (45 gallon) and install it yourself for less than that.

Hell if I lived near you I’d help your for a bottle of Irish whiskey...

My bad, just checked Lowe’s and an AO 20 gal is between $380 and $480....

quote:

Originally posted by MikeinNC:
You can go to any big box and buy a heater for around $800 (45 gallon) and install it yourself for less than that.

Hell if I lived near you I’d help your for a bottle of Irish whiskey...

My bad, just checked Lowe’s and an AO 20 gal is between $380 and $480....

You are spot on Mike ... ! I have replaced a couple hot water tanks over the years both gas and electric so I know this is literally plug-n-play. A little background: I acted as my own contractor when I built my house in 1987 doing all the electrical (400 amp service) and all the copper plumbing. Though older, I am comfortable doing this work myself.

Not wanting to swap out the 12/2 20 amp with 10/2 30 amp ... I can get an AO Smith for $400 and swap out the 4500 watt elements for 3800 watt and keep the original wiring.

And since I am married to a Newfie Irish woman ... there is always a bottle of Irish whiskey for you someday when our paths cross, just because.

Yesterday I bought a 30 gal water heater with two 4500 watt elements. Most water heaters, like the one I bought, only run one element at a time ... not both at once.

Today I swapped out each of the two 4500 watt elements with 3500 watt elements. This will easily meet the wiring and breaker limitations that I have.

What I am wondering ... is if the 4500 watt element requires 10 gauge wire with a 30 amp breaker, then why is the connection wiring at the top of the water heater 12 gauge wire ? Is the 10 gauge wire (for the 4500 watt element) more important for the length of run to the panel box than it is for the water heater itself ?

Many times an equipments wiring is undersized by normal standards. They have special requirements and have spec'd their unit very carefully.

20 amp heating circuit can only be loaded to 80%, which is 16 amps.
4500 watts ÷ 240 = 18.75 amps, hence the requirement for 10 GA wire.

The other factor is that 12 GA wire has to be protected by a 20 amp breaker and there goes the 80% rule again.
10 GA can be protected by a 30 amp breaker.

quote:

Originally posted by Excam_Man:
Many times an equipments wiring is undersized by normal standards. They have special requirements and have spec'd their unit very carefully.

20 amp heating circuit can only be loaded to 80%, which is 16 amps.
4500 watts ÷ 240 = 18.75 amps, hence the requirement for 10 GA wire.

The other factor is that 12 GA wire has to be protected by a 20 amp breaker and there goes the 80% rule again.
10 GA can be protected by a 30 amp breaker.

Exactly, and the reason (per my original post) where I am replacing on old water heater that is on 12 awg wire with a 20 amp breaker and not wanting to upgrade to the 10 awg with 30 amp breaker. Reason why today I swapped out the 4500 watt elements with 3500 watt. Doing the math (Ohm's Law) = 14.58 amps ... under the 80% for the 20 amp breaker.

Sounds to me like you figured it out.... I would have gone with the smaller water heater but what you did works for me... I'd have never thought of switching out the elements.

quote:

Originally posted by Blume9mm:
Sounds to me like you figured it out.... I would have gone with the smaller water heater but what you did works for me... I'd have never thought of switching out the elements.

I am replacing the old 50 gallon with a 30 gallon so it is a smaller tank. What is interesting is that it is difficult to find a 30 to 50 gallon tank that comes with 3800 or 3500 watt elements and the ones I did find need to be special ordered or from a speciality plumbing store ... and they cost more and delivery date is too far out as I am on a bit of a time crunch. With stores that buy in bulk it makes more sense for them to have on hand what the majority of the population is using and that is water heaters with 4500 watt elements. So buying a 30 gallon water heater with 4500 water elements was cheaper, have it now and swapping out the elements was both easy and inexpensive.

As I am pulling out the old water heater ... the ouside label shows 4500 watt elements, but thank goodness the elements installed showed to be 3500 watt. They showld of written such on the outside of the water heater to show the change conversion, something that I will be doing.