Ask Experts Questions for FREE Help !
Ask
    pika2018's Avatar
    pika2018 Posts: 1, Reputation: 1
    New Member
    		  
    #1

    Mar 17, 2017, 11:47 AM
    Is it safe to hook up a 240 volt single phase water heater to a 277 volt source
    I'm replacing a defective 277 volt, single phase, 3kw water heater with a 240 volt water heater. Is it safe to hook-up?
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
    Expert
    		  
    #2

    Mar 17, 2017, 01:24 PM
    Several concerns:

    1. First is that using an appliance intended for a 240 volt circuit on a 277-volt line is a code violation, assuming the water heater manufacturer's instruction manual specifies power must be 240 volt.

    2. If you decide to proceed anyways, the heater element will draw about (277/240)^2 = 1.33 times the power that it's designed for, so internal fuses and/or the heating element may overheat and burn out in short order.

    3. 240 appliances expect to be connected with two hot leads (each 120 volt relative to ground and 180 degrees out of phase with each other) plus a ground, plus (sometimes) a neutral - this neutral may be required so that the appliance has 120 volt power for ancillary circuits such as a timer. When connecting to 277 volts the leads are hot, neutral and ground, so there is no provision for a 120 volt circuit. If your heater requires such a connection the 277 volt wiring won't work.

    4. If there is an internal transformer in the water heater that is intended to convert 240 volts to 120 volts in order to power electronic controls, applying 277 volts could over-power the electronics.

    Bottom line is: I wouldn't recommend it.
    massplumber2008's Avatar
    massplumber2008 Posts: 12,832, Reputation: 1212
    Senior Plumbing Expert
    		  
    #3

    Mar 21, 2017, 07:32 PM
    Totally agree with ebaines!

    You can always check specifics with the product manufacturer... otherwise, just like ebaines, I can't recommend this!

    Mark
    caibuadday's Avatar
    caibuadday Posts: 460, Reputation: 10
    Full Member
    		  
    #4

    Mar 25, 2017, 06:23 PM
    I think you need an electrician with license to replace that heater. 277 v is usually for commercial or industrial and it is a single hot but 220v is two hot .
    ma0641's Avatar
    ma0641 Posts: 15,675, Reputation: 1012
    Uber Member
    		  
    #5

    Mar 26, 2017, 10:30 AM
    "but 220v is two hot". True but, AC power today is 120/240.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Convert 240 volt 3 phase to 220 volt single phase [ 2 Answers ]

Hi I have a 3 phase 250 volt 30 amp socket .I want to know if I drop one leg and change the receptacle . Can I plug a 200/230 volt 48/42 amp miller welder in to it ? Do I just wire nut the extra wire or pull it out of the panel ? Thanks mike

Can you operate a light fixture rated for 240 volt, on 208 volt single phase? [ 1 Answers ]

I have an old street light that has a multi tap ballast, the only markings that I can read on the wires are 240volt. My system is 3phase 208 volt and I was told that I could get a 2 pole breaker and the fixture would work. Is this the case?

I have 480 volt, three phase available. Can I pull 240 volt, single phase off this ? [ 1 Answers ]

Have available 3 phase, 3 leads plus a ground. Need to run 240 volt, single phase connection off the 3 phase. Is this possible without a step down transformer?

Can I use a residential water heater if I have only 277/480 volt 3 phase? [ 5 Answers ]

I am needing to install a residential water heater and I only have 277/480 volt 3 phase available. Are there residential water heaters that would be compatible with the voltage? I have found those that have a 240 volt system with a 277 volt element would this work with 277 3 phase?

Advantages of a 480/277 3 phase Volt system over a 120/240 [ 2 Answers ]

I have customer that needs to upgrade his service from 800Amps to 1200Amps. He currently has a 120/240V 3 phase system and a 120/240V System With 2 separate Meters. I am advising that he upgrade and go to a 1200Amp 480V 3 phase system and transform down for existing loads. Will he save any costs on...

View more questions Search