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glinka
wire size

I have a room with 14-2 wire for lights and outlets. It was fine until we started to use a treadmill. Sometimes the breaker would blow. So I replaced 15 amp with 20 amp. Is this a problem if only using treadmill 30 minutes at a time?

A. Spruce
Re: wire size

Bad idea! Go back to a 15a breaker because you want the breaker to be the weakest link in the chain, not the wire.

My suspicion is that you've got bad connections between the breaker and the outlet used for the treadmill, or the treadmill overloads an already heavily used circuit. Try plugging the treadmill in somewhere else and see if you still have a breaker popping issue, if so, it could be a problem with the treadmill.

keith3267
Re: wire size

All electrical appliances have an information plate on them that gives you the maximum draw. If it greater than 15 amps or 1650 watts, you need to find another room.

Brad
Re: wire size
keith3267 wrote:

All electrical appliances have an information plate on them that gives you the maximum draw. If it greater than 15 amps or 1650 watts, you need to find another room.

15 amps @ 120 volts is 1800 watts. Where does 1650 watts come from?

A. Spruce
Re: wire size
brrichter wrote:

15 amps @ 120 volts is 1800 watts. Where does 1650 watts come from?

Circuits are not rated at full amp draw, hence the lesser number.

How this relates to the OP's original question is that if the treadmill pushes the circuit over the total amp draw, it's going to pop the breaker. If the breaker is upgraded without upgrading the wiring, the wire itself becomes the weak link and can break, fault, burn, and otherwise cause a nightmare that nobody wants. 14g wire is not rated for a 20a breaker, hence my recommendation to return the breaker to a 15a rating and relocate the treadmill or diagnose the treadmill and circuit to determine why it's faulting at a sub par load.

Brad
Re: wire size
A. Spruce wrote:

Circuits are not rated at full amp draw, hence the lesser number.

How this relates to the OP's original question is that if the treadmill pushes the circuit over the total amp draw, it's going to pop the breaker. If the breaker is upgraded without upgrading the wiring, the wire itself becomes the weak link and can break, fault, burn, and otherwise cause a nightmare that nobody wants. 14g wire is not rated for a 20a breaker, hence my recommendation to return the breaker to a 15a rating and relocate the treadmill or diagnose the treadmill and circuit to determine why it's faulting at a sub par load.

Circuits are absolutely rated at full amp draw. Your information is wrong. A 15 amp circuit may be loaded to 15 amps provided the load is non-continuous.

A. Spruce
Re: wire size
brrichter wrote:

Circuits are absolutely rated at full amp draw. Your information is wrong. A 15 amp circuit may be loaded to 15 amps provided the load is non-continuous.

You just proved my point. Yes, you can draw 15 amps, but only for a very short amount of time, about the amount of time it takes to spin up a motor, any more than that and you're going to blow the breaker. Hence why circuits are downgraded.

Re: wire size
brrichter wrote:

Circuits are absolutely rated at full amp draw. Your information is wrong. A 15 amp circuit may be loaded to 15 amps provided the load is non-continuous.

(Y) (Y) yeah agreed with you

Brad
Re: wire size
A. Spruce wrote:

You just proved my point. Yes, you can draw 15 amps, but only for a very short amount of time, about the amount of time it takes to spin up a motor, any more than that and you're going to blow the breaker. Hence why circuits are downgraded.

That is so wrong it is laughable.

keith3267
Re: wire size

Let me explain the 1650 watts. Your 120 volt outlet is part of a circuit that includes the secondary windings on the transformer on the pole outside your house, the wires from it to your power meter, the buss bar and circuit breakers in your panel, the wires from your panel to the outlet and what ever load you have plugged into that outlet.

The transformer will provide 120 volts under no load condition. That there are no appliances or lights plugged in or on. No current is flowing in the circuit so no voltage is dropped in the circuit except at the open end where all 120 volts are dropped.

Each of these components in the circuit have some resistance to current flow. When a load is applied, all these resistances will drop some of that 120 volts. For that reason, a 120 volt circuit is expected to provide 110 volts at an outlet when the circuit is loaded. The actual voltage will vary based on the size of not only that load, but all loads from the secondary of the transformer.

So my calculation was 110 volts times 15 amps which equals 1650 watts. For more information, google Kirchoff's Law.

Brad
Re: wire size
keith3267 wrote:

Let me explain the 1650 watts. Your 120 volt outlet is part of a circuit that includes the secondary windings on the transformer on the pole outside your house, the wires from it to your power meter, the buss bar and circuit breakers in your panel, the wires from your panel to the outlet and what ever load you have plugged into that outlet.

The transformer will provide 120 volts under no load condition. That there are no appliances or lights plugged in or on. No current is flowing in the circuit so no voltage is dropped in the circuit except at the open end where all 120 volts are dropped.

Each of these components in the circuit have some resistance to current flow. When a load is applied, all these resistances will drop some of that 120 volts. For that reason, a 120 volt circuit is expected to provide 110 volts at an outlet when the circuit is loaded. The actual voltage will vary based on the size of not only that load, but all loads from the secondary of the transformer.

So my calculation was 110 volts times 15 amps which equals 1650 watts. For more information, google Kirchoff's Law.

One can assume any numbers one wants to reach a desired result. Automatically assuming an 8% voltage drop right off the bat makes no sense to me.

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