water heater disconnect

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peter d said:
How many GPM, KW, voltage, etc?
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I can look tomorrow, if it interests you. It is eEmax brand, but it's about twice as wide as the one in the picture, and black in color. I already know it's a 208 unit, being served at 240.
 
Just had a project where we put a bunch in a VA hospital. Used twist lock's for the disconnect. Lots less $$ than a second box for a switch. They were added to existing hand wash sinks. Had to add an additional 480-120/208V transformer and panelboards there were so many. Had to up size the wire size for voltage drop, though.

RC
 
glene77is said:
Can you use a Double-Pole 20Amp snap switch,
with both poles in parallel?
Total contact rating would be 40Amp.
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No, in parallel or not the switches rating remains 20 amps as far as the NEC is concerned.
 
glene77is said:
Can you use a Double-Pole 20Amp snap switch,
with both poles in parallel?
Total contact rating would be 40Amp.
Click to expand...
You can actually increase the current-breaking capability of contacts by placing them in series rather than parallel. It effectively opens the contacts twice as fast and extinguishes the arc faster for less contact pitting.

Added: Paralleling contacts does decrease contact resistance, but no two contact sets open at exactly the same time, so one set still bears the brunt of damage from arcing during the contacts opening under load.
 
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Horrible memories...

Horrible memories...

220/221 said:
The 15 tripped so I changed it to a 20, then a 30...which still tripped.

The 40 seemed to fix it but I put in a 50 just to be safe.
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Way back when, when I worked at AutoZone, there was a guy who was trying to replace the fuse for his headlights with a gum stick wrapper (the kind with the foil on it). I kept trying to tell him it wouldn't work, as he argued it would, while inhaling the smoke coming out of the fuse box, as I stood behind him with the fire extinguisher...I guess a 40 amp fuse wouldn't have fixed that problem.

220/221, thanks, I had almost completely repressed that memory. Along with the memory of someone arguing that $9.99 was way too much for brake pads, since he could go down to pick and pull and get them (used) for $5.

sometimes, some people scare me.:grin: :cool: :roll:
 
mdshunk said:
I can look tomorrow, if it interests you. It is eEmax brand, but it's about twice as wide as the one in the picture, and black in color. I already know it's a 208 unit, being served at 240.
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I've been waiting all day for the answer. ;)

All kidding aside, I really am curious to see how big one of those instantaneous units has to be before it's out of the "lame" category.
 
peter d said:
I've been waiting all day for the answer. ;)

All kidding aside, I really am curious to see how big one of those instantaneous units has to be before it's out of the "lame" category.
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Sorry, I really completely forgot. I've been in over my head all week, and this is only Tuesday. Dimensionally, it's twice as wide as the one I pictured, but about as tall.
 
mdshunk said:
Sorry, I really completely forgot. I've been in over my head all week, and this is only Tuesday. Dimensionally, it's twice as wide as the one I pictured, but about as tall.
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When you get your head above the pile of poo that you're in, let me know what you find out. :)
 
I once had to install a 120V, 70A circuit to a UPS. It was fed from a 3 phase 120/208 QO panel. Square D's largest single pole QO is 70A. Really played havoc with load balance.:wink: Never understood requirement for 120V input for UPS.
 
Ragin Cajun said:
Just had a project where we put a bunch in a VA hospital. Used twist lock's for the disconnect. Lots less $$ than a second box for a switch.

RC
Click to expand...

If money was the deciding factor, I would have utilized 422.31(B) and simply put a breaker lock on the circuit breaker.
 
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