# hypothetical question

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#### caosesvida

##### Senior Member
Re: hypothetical question

The wire size determines how many amps can go through without overheating the wire and damaging the insulation. A bare copper wire on a pole to a shed may be able to handle 100 amps, but in a house with regular romex it is rated to carry 20 amps unless it is drawing those amps for more than three hours. In which case the heat could build up and you need to derate the ampacity of the wire to allow for that. not sure if that is what you are asking.

#### charlie b

##### Moderator
Staff member
Re: hypothetical question

Originally posted by ephesus56ad:. . . what determines the amount of amps going through a wire? Is it the load at the end or combinations of loads on that wire?
Ohm?s Law determines the amps going through a wire. Amps will equal the voltage available at the supply point (let?s say the supply point is the breaker panel) divided by the total resistance of the path that the current will follow from the panel, through the wires, to the load or loads, along more wires, and back to the panel.

The wires themselves have some small amount of resistance, and that will have a small impact on the current flow. The thing that mostly determines the amps is the load or loads. For a hot tub, the 6/3 wire that you mentioned may be providing power to one or more motors, some heating elements, perhaps some lights within the tub, and a control box for operating all of that stuff. Anytime one more of these items is turned on, more amps will flow through the supply wire. It is the manufacturer?s duty to figure out how much total amps might be needed by the equipment, and to tell you that information in the instruction sheet.

Is that what you were asking about?

#### ephesus56ad

##### Member
Re: hypothetical question

Yes that is it. Thank you Charlie B.

I love coming to this forum, not only do I get the answers to my questions but alot of knowlege along the way.

Thank you all.

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