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Robert Runchey
07-27-2008, 08:06 AM
I have two questions to ask. I performed an inspection yesterday and observed an upper level window very closed to the roofing shingles. Can anyone tell the minimal allowable clearance from a window to the roof. I saw this question answered recently but can not find it.

Also, I know in most cases that breakers are not designed to except double tapping but are there breakers that do? I looked at a 100 amp GE panel & breakers with no open slots

Thanks, Bob

Jerry Peck
07-27-2008, 11:35 AM
Bob,

Most items need to be 2" minimum above the roof covering to help reduce moisture migration upward and to allow for roof replacement without having to disturb those items.

No, that is not one of the breakers allowed for two conductors.

No (to your unasked question regarding the transformer in that panel), that transformer is not allowed in the panel.

Robert Runchey
07-27-2008, 11:56 AM
Thanks Jerry. I have another question for you or anyone else that would like to chime in. I looked at a building the other day and one of the rooms had dark spots on a wall where the nails are located. Would this be an indication of moisture or maybe improper ventilation?

Jerry Peck
07-27-2008, 12:01 PM
My first thought was "ghosting", however, that is typically where you see rafters or trusses, or even studs in attic walls.

Being as you can see those many nails, I would check into both "ghosting" and high humidity (which could allow/cause moisture to condense on the nail heads, causing rusting.

It could also be something as simple as they did not finish the room properly, using one thin coat of drywall mud over the nail heads.

Joe Klampfer
07-29-2008, 06:13 PM
Also, I know in most cases that breakers are not designed to except double tapping but are there breakers that do? I looked at a 100 amp GE panel & breakers with no open slots


The double tqp you're referring to looks like a doorbell transformer tied into an existing breaker being used for another circuit, which is permitted up here anyway. There is an issue with the transformer being mounted inside the panel though - should be mounted externally. Also, a 20 amp breaker on a regular lighting circuit is of concern.

Jerry Peck
07-29-2008, 07:19 PM
The double tqp you're referring to looks like a doorbell transformer tied into an existing breaker being used for another circuit, which is permitted up here anyway.


Double taps are permitted there? Intentionally? By the AHJ? :eek:

Lee Nettnin
07-30-2008, 05:22 AM
Robert,
Does the house have a gas or wood fireplace (possible back drafting)? Or do the owners burn a lot of candles? Any of these coupled with not enough insulation could cause condensation on the nail heads and leave the 'dirt' behind.
Lee

Robert Runchey
07-30-2008, 04:52 PM
The entire building is electric and I'm not sure of the candles being used. All I know is that the nails that are obvious are right above an electric heater\air conditioner combo unit.

The rest of the building is clean with no signs of these spots.

Thanks for responding,

Bob

Jerry Peck
07-30-2008, 05:11 PM
All I know is that the nails that are obvious are right above an electric heater\air conditioner combo unit.

Possibly cold air leaking into the wall cavities from the a/c unit.

Next time you see something like that, if you have an IR thermometer take a reading on the wall surfaces to each side of that area, then on the wall surfaces in that area. If cold air is leaking into the wall cavities, that will cause the wall surface to be cooler, and the IR thermometer will read that difference.

Robert Runchey
07-30-2008, 05:22 PM
I did a scan of the area with an infrared camera but the surfaces all pretty much look the same. I didn't have much difference in the indoor and outdoor temperature but the wall just above the heat\ac unit was a few degrees cooler. :D

Thanks Jerry.

John Allingham
08-13-2008, 04:23 PM
The double tqp you're referring to looks like a doorbell transformer tied into an existing breaker being used for another circuit, which is permitted up here anyway. There is an issue with the transformer being mounted inside the panel though - should be mounted externally. Also, a 20 amp breaker on a regular lighting circuit is of concern.


Joe
You sure about that? Double tapping of the doorbell transformer is not allowed in Ontario (although I see it all the time).

Jim Robinson
08-13-2008, 05:11 PM
What is the concern of a 20 amp circuit for lighting? Is it just that you normally see a 15 amp circuit? I wouldn't be concerned about it as long as the wire size was correct, but I wanted to know if there was something I was missing.

How did you know it was a lighting circuit?

Joe Klampfer
08-13-2008, 10:32 PM
Joe
You sure about that? Double tapping of the doorbell transformer is not allowed in Ontario (although I see it all the time).


I've not worked as an electrician for about 22 years but it was acceptable back then and I too still see it done lots of times now, but with the transformer mounted on the outside of the panel through a knockout.

Joe Klampfer
08-13-2008, 10:38 PM
How did you know it was a lighting circuit?

Actually, I didn't. I was just guessing. Up here anyway, they don't allow 20 amp circuits for residential lighting or standard receptacle circuits.

Jerry Peck
08-14-2008, 05:41 AM
The double tqp you're referring to looks like a doorbell transformer tied into an existing breaker being used for another circuit, which is permitted up here anyway.


Joe
You sure about that? Double tapping of the doorbell transformer is not allowed in Ontario (although I see it all the time).


I've not worked as an electrician for about 22 years but it was acceptable back then and I too still see it done lots of times now, but with the transformer mounted on the outside of the panel through a knockout.


Joe,

Down here, back 20-30+ years ago it was 'not thought about', meaning it was 'allowed' too, as in 'allowed to be done because no one thought about it not being allowed', however, it was not allowed back then either (as it turned out to be once many of of HIs started asking questions about it).

Electricians did it mainly because it was simple and easy, and that they did it the way they were taught to do it ... just turns out that it was never allowed ... just not thought about 'back then'.

Joe Klampfer
08-14-2008, 10:30 PM
Joe,

... just turns out that it was never allowed ... just not thought about 'back then'.

I don't disagree, in fact, you're probably right. It was "just not thought about back then" likely because a class 2 doorbell transformer draws next to nothing in terms of load amps and nobody really cared (and it was easily accessable) - provided it was installed / mounted properly.

enough said...