electrical on "Powered Attic Gable fan"


Old 08-17-06, 02:00 AM
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electrical on "Powered Attic Gable fan"

I just installed a Power Attic Gable Fan with a thermostat. I have used 14/2 with ground wiring. At this time I have already ran the wiring to the breaker box---(not hooked up yet, wire just hanging there).

I was wondering before I purchase a breaker, could I just tie in to an existing outlet? I have an electrical outlet for my garage door opener just couple feet away. Could this be tied into here?

One other wire is close by, but that is from a light switch. I need power available for when thermostat kicks in, so this would be out I think.

I think a breaker (am assuming 15amp) would cost about $40 or so. Just thinking of ways to not spend anymore than necessary and still be safe.

Also, since I don't work with electrical wiring very often, I want to ask before proceeding. My history with electrical wiring is on existing wiring, outlets, etc. This just a tad different.

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Old 08-17-06, 05:24 AM
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Certain circuits can be tapped. Others cannot. You limited yourself by using 14-2 wiring (a mistake in my opinion), so you can only safely tap a 15 amp circuit.

Generally speaking, circuits serving bathrooms, kitchen counter tops, dining room receptacles and laundry ares cannot be tapped. A circuit serving a garage door opener can legally be tapped, but you need to understand the entire load on a circuit. You should not tap a circuit that is already heavily loaded, because of the possibility of tripping the circuit breaker.

Whether or not you could tap the light switch for power depends on if the switch is wired as a switch loop or if it has a neutral wire. It also, of course, depends on what the circuit presently has on it.

A general purpose circuit breaker does not cost $40. These are usually less than $10. However, you need a breaker designed and approved for your panel, not just any breaker, or even any breaker that fits.
Old 08-17-06, 09:16 AM
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Power gable vents for residences are very small fractional hp motors some as small as 1/15 hp up to I think around 1/6 hp. As Bob said you are somewhat limited due to the 14 awg wire and needing 15 amp circuit to tap. A garage door opener for a typical 9x7 door can be 1/4 to 1/2 hp so somewhere between 5 and 10 amps depending on hp. Another thing to consider is do you have more than one opener on the same branch circuit. I've seen many residences with two on a 15 amp circuit. If that is your case I'd look for another code compliant circuit to tap. All in all gable vents dont pose problems with a reasonably loaded branch circuit. So in a nutshell find a circuit other than the ones Bob mentioned and determine what loads are on it and consider how often those loads are applied to the circuit at the same time. Then see if the sum of those loads in amps will allow the gable vent fan to be added and not exceed the branch circuit rating. Be mindful of branch circuits that have motors on them because motors have initial high starting currents before they drop back to their running amps. If you bump a circuit to its max or close to it you may have a breaker trip when a motor starts. It is generally recommended that a 15 amp branch circuit not be loaded to more than 12 amps.

Old 08-17-06, 02:13 PM
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Running now!

I told you wrong on the circuit breaker. While looking in my breaker box==most were 20amp breaker--few for stuff like air conditioning etc. were bigger.

So, I just got another 20amp breaker. I wired the Attic fan to that --- it is only thing going to that breaker at the moment.

Cost was only about $10 or $11 for the breaker.

Seems to be running fine so far.

The fan is a "Master Flow Power Attic Ventilator Pro 3".

I got to check on one thing. I noticed much of the wiring in attic was 14\2 with ground. The smallest breaker in my box is 20 amps. Most are 20 amps. Somewhere, I think on instructions with the fan, said that a 15 amp breaker requires a minimum of 14 guage wire. A 20 amp breaker requires a minimum of 12 guage wire.
I am assuming that this standard came in after my home was built. About 1979.

Is the 14/2 wire going to be ok with the 20 amp breaker just as with other wires?

Thanks for the help guys.
Old 08-17-06, 02:51 PM
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No, the 14 Ga. wire need to be protected by a 15 amp breaker. The 20 amp breaker will not provide the protection that the 14 ga. wire requires and could lead to a fire.

Replace the breaker now, before you forget.
Old 08-17-06, 03:34 PM
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Any circuits that are in your house that have 14 gage wire MUST be protected by 15 amp breakers. ASAP find and correct these fire hazards.
Old 08-17-06, 03:48 PM
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Got that one fixed.

I went immediately and purchased the 15amp breaker and installed it in place of the 20amp as you instructed.

Now, apparently, my wiring has many 20amp breakers and I have seen 14/2 wiring in a few places. I was thinking that an electrical outlet(plug) I replaced had the same wiring, but not real sure.

If this is the case and 14/2 wiring has been used extensively in my home, then all of the 14/2 needs to be on 15amp breakers?

If this is the case, when I replace all 20amp breakers with 15 amp breakers, will there be things that don't work etc. because maybe something is tied into the same breaker? I assume if that is the case--then just add more breakers? Only have about 2 or so slots left.

I am wondering why my wiring is like this. Could this have been ok with code back in 1979 when house was built? The wiring I am seeing appears to be original.
Old 08-17-06, 04:15 PM
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It was never code to have 14 gage wiring on 20 amp circuits (that I know of).

The likely scenario is that some idiot who owned the house before you (or sometime before you) put in 20 amp breakers because of nuisance trips.

You may very well experience these trips. If you do, you can either move your lights and appliances things around, or you can split some of the circuits. Splitting circuits, however, is nor necessarily an easy thing to do.
Old 08-17-06, 04:20 PM
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Thanks guys. I will look into it.
Old 08-19-06, 08:48 AM
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I would take a look at the wiring at a couple of outletes and see if they are also wired with 14 guage wire. I hope not. It could be that the wiring you are seeing is all for lighting which would be OK. It would nt be the first house I have seen where all the light cirxuits are fused for 20 amps.

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