water heater disconnect

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bob j

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I'm wiring an instant hot type of water heater.It is single phase 120v and 3.5 kw. My question is- Can I use a 30 amp single pole snap switch as a disconnect even though the only ones I can find are only rated for 24 amps?
 
bob j said:
I'm wiring an instant hot type of water heater.It is single phase 120v and 3.5 kw. My question is- Can I use a 30 amp single pole snap switch as a disconnect even though the only ones I can find are only rated for 24 amps?
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Are you sure this is a 120 unit. 3.5 kw at 120 volts is 29 amps. You then need to multiply by 1.25 and you would need a 40 amp circuit 120v. I have never seen a 40 amp 120volt breaker
 
chevyx92 said:
I've seen single pole 50A breakers so I would imagine they make a 40A.
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Yes, perhaps they do but why would someone make a heater that was 120v and 3.5 kw. That's is just silly.
 
Dennis Alwon said:
Yes, perhaps they do but why would someone make a heater that was 120v and 3.5 kw. That's is just silly.
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It's very common for the instantaneous heaters to be that way. But I agree, it's silly. :)
 
I would like to see the specs. I know GE makes a single pole 40<<< I agree with the others, this is silly!!
 
resistance said:
I would like to see the specs. I know GE makes a single pole 40<<< I agree with the others, this is silly!!
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As a matter of fact I had to wire and install some 277 volt insta-hots that required a 40 amp circuit. It was on old Westinghouse style breaker and the supply house had to order the breaker because single pole 40 amp, 277 volt Westinghouse/Cutler Hammer breakers aren't very common. ;)
 
I had to use a single 40 to refeed an old 120V cooktop when I changed a fuse panel out for a breaker panel. Not too many uses for single 40's.
 
I was in a code class once and the instructor told us a story about an argument he had w/ a guy in the class about the existance of 120V 55A circuit breakers. He said after a few minutes, the guy went to his truck and grabbed a few of them to show. Apparently, this guy did work on a military installation in florida and they were custom ordered for a job there.
 
brantmacga said:
Apparently, this guy did work on a military installation in florida and they were custom ordered for a job there.
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:grin: Oh boy! If I were that guy, I'd have told the instructor that I bought them at Home Depot, and they sell them there every day. :grin:
 
mdshunk said:
:grin: Oh boy! If I were that guy, I'd have told the instructor that I bought them at Home Depot, and they sell them there every day. :grin:
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ha! I wouldn't expect any less from you :wink:
 
mdshunk said:
:grin: Oh boy! If I were that guy, I'd have told the instructor that I bought them at Home Depot, and they sell them there every day. :grin:
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I would take one to Home Depot, and tell the guy working the aisle that I had bought it there the day before, and I needed another one.... :wink:
 
Dennis Alwon said:
Are you sure this is a 120 unit. 3.5 kw at 120 volts is 29 amps. You then need to multiply by 1.25 and you would need a 40 amp circuit 120v. I have never seen a 40 amp 120volt breaker
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How does the 1.25 factor come into this calculation? Are you considering an insta-hot a continuous load?
 
continuous load?

continuous load?

infinity said:
How does the 1.25 factor come into this calculation? Are you considering an insta-hot a continuous load?
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I didn't think an instant hot water heater fell under the heading of continuous load, because it isn't a storage type heater.422.13:confused:
 
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