45 amp riser

nickelec

Senior Member
Location
US
Can anyone put in layman's terms how to explain to a customer that 2 45 amp fuses that feed a riser does not mean that you have 90a loo

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480sparky

Senior Member
Location
Iowegia
You have 100 psi in water pressure coming into your home's plumbing system. Having 100 psi at the hot and 100 psi at the cold at the faucet does not make 200 psi.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
I had to try to explain this to a guy at work years ago.
I had him put a rope around a pole, and pull each side one at a time like he is sawing the pole in half with the rope...
12 pounds of pull with one arm while the other arm is being pulled to the pole, then 12 pounds of pull with the opposite arm while the original arm is pulled to the pole doesn’t equal 24 pounds...
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Can anyone put in layman's terms how to explain to a customer that 2 45 amp fuses that feed a riser does not mean that you have 90a loo

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Not when I had a customer recently ask if we could use two 30a GFCI breakers to supply a new hot tub that called for a 60a GFCI-protected circuit. Umm, no. :happysad:

Bad enough that I had to install a separate box with the 60a GFCI, because the pool panel is a Sq-D QO box, and the QO260GFI breaker has no load neutral terminal.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
On my hot tub, everything was 240 volt, so I did not need a load neutral, just the line neutral to power the breaker electronics. Probably the same way that one works.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
On my hot tub, everything was 240 volt, so I did not need a load neutral, just the line neutral to power the breaker electronics. Probably the same way that one works.
No, I wired it. The instructions were very clear about it. There was a neutral terminal and it had wires connected to it on the circuit board.

Granted the neutral load is a fraction of the required circuit, like most major loads like appliances, but when it's needed, it's needed.
 

kwired

Electron manager
Location
NE Nebraska
The hot/cold water and rope pull explanations are not 100% analogous to multiwire voltage source though

As mentioned OP can have two 45 amp loads at 120 volts or he can have one 45 amp load at 208 volts.

More confusion for those that don't know how this works - that is 10800 VA total ability at 120 volts but only 9360 at 208. gets more complex when there is combination of 120 and 208 volt loads.
 

480sparky

Senior Member
Location
Iowegia
The hot/cold water and rope pull explanations are not 100% analogous to multiwire voltage source though

As mentioned OP can have two 45 amp loads at 120 volts or he can have one 45 amp load at 208 volts.

More confusion for those that don't know how this works - that is 10800 VA total ability at 120 volts but only 9360 at 208. gets more complex when there is combination of 120 and 208 volt loads.
Remember who the audience is for this explanation.
 

kwired

Electron manager
Location
NE Nebraska
Remember who the audience is for this explanation.
I know, still situations can come up that it don't quite work out as described.

Now bring in the third phase conductor and explain that with same analogy. you might come sort of close but not exactly the same as how electrical works.

How do you get phase angles out of a hydraulic system?
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
The hot/cold water and rope pull explanations are not 100% analogous to multiwire voltage source though

As mentioned OP can have two 45 amp loads at 120 volts or he can have one 45 amp load at 208 volts.

More confusion for those that don't know how this works - that is 10800 VA total ability at 120 volts but only 9360 at 208. gets more complex when there is combination of 120 and 208 volt loads.
Don’t get technical...
if the people don’t get the water or rope explanations they are far from complex power formulas and explanations...

you got to crawl before you can walk
 
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