Hooking up a Water Heater
Hooking up a Water Heater
(OP)
I was ask to hook up a single phase water heater. The label on the water heater says: 208v or 240v. The power they had was 480v/277v (Wye). Would it be safe to hook up the 277v to the water heater.
Thanks Nod
Thanks Nod





RE: Hooking up a Water Heater
RE: Hooking up a Water Heater
This is a misapplication. Resistive power dissipation increases with the square of voltage ratio. Your proposal is hazardous and the heater will likely fail in a short interval.
RE: Hooking up a Water Heater
Thanks Don
RE: Hooking up a Water Heater
“higher voltage there would have been lower amps” won’t work, and will get you into trouble. You have a constant-resistance application, not constant-power. An appropriate size of 277 - 120/240 Volt dry transformer can do the job. An example is page 17 of http://www.federalpacific.com/literature/drytrans/FPTS-RTB-0701.pdf
RE: Hooking up a Water Heater
RE: Hooking up a Water Heater
1. Increase current by 277/240 = 15%
2. Increase electric & heat power by (15%)**2 = 33%
33% is a big increase.
Can't say for sure if what you're proposing is safe, you'd need to check with the manufacturer or UL.
But we can say for sure that if it works, it won't last long.
As was mentioned, buck/boost transformers (small 1-phase autotransformers) are commonly available from all the usual transformer suppliers.
RE: Hooking up a Water Heater
peebee, the heater may not be intended to operate on other than a 120/240 or 120Y/208 system, making the buck-boost transformer a misapplication.
RE: Hooking up a Water Heater
RE: Hooking up a Water Heater
RE: Hooking up a Water Heater
As a condition of listing and labeling, some ‘2-wire’ 200-230V electrical equipment is labeled "120/240V" or “for operation at not more than 150V-to-ground,” ostensibly to limit voltage from phase-to-ground on the equipment internals. This is not possible with a 277-240 buck transformer. Operation in the suggested manner may void NRTL listing.
RE: Hooking up a Water Heater
Red star for you.
RE: Hooking up a Water Heater