Doorbell Transformer in Panel
- Thread starter roc
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Doorbell Transformer in Panel
No it would violate the panel manufactures instructions unless the doorbell transformer was listed and identified by the panel mfg to allow it to be installed inside see 110.3(B)
And its a violation of 725.54
Why would this be considered? Most door bell transformers have a set screw to hang it from an 1/2" KO, it seems like what is proposed is a lot harder.
No it would violate the panel manufactures instructions unless the doorbell transformer was listed and identified by the panel mfg to allow it to be installed inside see 110.3(B)
And its a violation of 725.54
Why would this be considered? Most door bell transformers have a set screw to hang it from an 1/2" KO, it seems like what is proposed is a lot harder.
marissa2
Senior Member
- Location
- Connecticut
Re: Doorbell Transformer in Panel
When I moved into my newly built house 17 years ago the first thing I did was open the panel. What do you tnink I found. The transformer was sitting on bottem of the panel and the bell wire was running up the inside and out through a NM connector with a line voltage cable. That didn't stay there too long.
Lou
When I moved into my newly built house 17 years ago the first thing I did was open the panel. What do you tnink I found. The transformer was sitting on bottem of the panel and the bell wire was running up the inside and out through a NM connector with a line voltage cable. That didn't stay there too long.
Lou
Re: Doorbell Transformer in Panel
Tom ... good point about the listing/labeling, but assuming the panel [and transformer] instructions don't prohibit that, I dont see the violation under Article 725.
It seems like 2002 NEC 725.55(D) would permit it, if one of two simple requirements was met ... but the "intruduced solely to connect the equipment" part seems a little sticky.
I am not advocating doorbell transformers in panels here, and it is very simple to just put one on the outside of a panel. I am just trying to find the applicable code sections that address this issue.
Rob
[ November 25, 2003, 07:04 PM: Message edited by: roc ]
Tom ... good point about the listing/labeling, but assuming the panel [and transformer] instructions don't prohibit that, I dont see the violation under Article 725.
It seems like 2002 NEC 725.55(D) would permit it, if one of two simple requirements was met ... but the "intruduced solely to connect the equipment" part seems a little sticky.
I am not advocating doorbell transformers in panels here, and it is very simple to just put one on the outside of a panel. I am just trying to find the applicable code sections that address this issue.
Rob
[ November 25, 2003, 07:04 PM: Message edited by: roc ]
Re: Doorbell Transformer in Panel
Residential door bell transformers are designed and intended to be installed in ambient temperature locations. The interior of a panel is not ambient temperature. I have a problem with installing them in attic spaces for the same reason.
Bell wire is not insulated for the highest voltage in a panel.
Residential door bell transformers are designed and intended to be installed in ambient temperature locations. The interior of a panel is not ambient temperature. I have a problem with installing them in attic spaces for the same reason.
Bell wire is not insulated for the highest voltage in a panel.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Doorbell Transformer in Panel
I always put them on the handy box for the furnace switch as it alway in the same place. I can not count the times I have hade to try to find the transformer when repairing the door bell. In the attic, panel, crawl space Etc...
A common location would be nice when you need to find it. I used to put them on a pull chain box in the basment or crawl space but after a few times of the home owner dry walling the basment and covering it up fixed my thinking on that one.
I always put them on the handy box for the furnace switch as it alway in the same place. I can not count the times I have hade to try to find the transformer when repairing the door bell. In the attic, panel, crawl space Etc...
A common location would be nice when you need to find it. I used to put them on a pull chain box in the basment or crawl space but after a few times of the home owner dry walling the basment and covering it up fixed my thinking on that one.
Re: Doorbell Transformer in Panel
The sheetrocking mentioned above could be the issue of the original post.For example I just wired a house with a grannie suite with its own panel fed off a 100 amp breaker in the main panel.The problem was the sub was flush mounted and left me nowhere I could think of to mount the X former....so I had the same question.I searched for a panel divider of sorts but came up empty.I ended up setting an octagon inside a closet,above the door and mounting the xformer on a round cover with a KO in it.BTW the whole house was sheetrocked which is becoming more and more popular around here.Seems foolish to me for future changes/add ons etc. Ross
The sheetrocking mentioned above could be the issue of the original post.For example I just wired a house with a grannie suite with its own panel fed off a 100 amp breaker in the main panel.The problem was the sub was flush mounted and left me nowhere I could think of to mount the X former....so I had the same question.I searched for a panel divider of sorts but came up empty.I ended up setting an octagon inside a closet,above the door and mounting the xformer on a round cover with a KO in it.BTW the whole house was sheetrocked which is becoming more and more popular around here.Seems foolish to me for future changes/add ons etc. Ross
dirkhats
Member
- Location
- West Jordan, Utah
Re: Doorbell Transformer in Panel
The real problem I see with installing these transformers inside of boxes is with 300.3(C)(1) which reads as follows:
"600 Volts, Nominal, or Less. Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway."
As stated here the real problem lies with the insulation of the class II wire which is not rated for the voltage in the panel or even the box located behind the door chime. As I see it, these are code violations. I support the idea of installing a separate box for the purpose of properly mounting the door chime transformer in an area like a furnace room. If the room is finished, us a blank cover with a 1/2" KO.
Dirk
[ November 29, 2003, 06:01 PM: Message edited by: dirkhats ]
The real problem I see with installing these transformers inside of boxes is with 300.3(C)(1) which reads as follows:
"600 Volts, Nominal, or Less. Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway."
As stated here the real problem lies with the insulation of the class II wire which is not rated for the voltage in the panel or even the box located behind the door chime. As I see it, these are code violations. I support the idea of installing a separate box for the purpose of properly mounting the door chime transformer in an area like a furnace room. If the room is finished, us a blank cover with a 1/2" KO.
Dirk
[ November 29, 2003, 06:01 PM: Message edited by: dirkhats ]
A
a.wayne3@verizon.net
Guest
Re: Doorbell Transformer in Panel
Charty,we also used a 2 gang box behind the chime.But that stopped 300 c 1 made that a past practice.Since the insulation is the key.So now we mount a single gang box above the panel(most panels are surface mounted with a 2x4 chase) 99% of our panels here are mounted on a block wall.Mount a single gang box above the panel feed it off of a circuit,and trim with a blank with a 1/2 in.ko and trans.surface mounted . Not as clean of an installation but its better than getting tagged.
Charty,we also used a 2 gang box behind the chime.But that stopped 300 c 1 made that a past practice.Since the insulation is the key.So now we mount a single gang box above the panel(most panels are surface mounted with a 2x4 chase) 99% of our panels here are mounted on a block wall.Mount a single gang box above the panel feed it off of a circuit,and trim with a blank with a 1/2 in.ko and trans.surface mounted . Not as clean of an installation but its better than getting tagged.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Doorbell Transformer in Panel
And as bennie has said mounting them in a attic is a no-no as all the newer transformers has a thermal fuse in the winding and once the temp has been reached it opens and the transformer has to be replaced. and the temp is not very high in them ether.
And as bennie has said mounting them in a attic is a no-no as all the newer transformers has a thermal fuse in the winding and once the temp has been reached it opens and the transformer has to be replaced. and the temp is not very high in them ether.
Re: Doorbell Transformer in Panel
Thanks for the input guys ... I am really trying to get a better handle on how serious a problem it is for an older panel to have a doorbell transformer in it.
Just out of curiosity, what code sections are quoted on the red tags ... would it be 110.3(B) since I am assuming the transformers are not listed/labeled to be installed in a panel?
It seems that 725.55(D) would supercede 300.3(C)(1) per 90.3 and 725.1 ... also see the FPN under 300.3(C)(1) and 725.1
As long as the existing low voltage wiring complies with 725.55(D) I don't see a clear code violation. Am I missing something here?
Thanks for the input guys ... I am really trying to get a better handle on how serious a problem it is for an older panel to have a doorbell transformer in it.
Just out of curiosity, what code sections are quoted on the red tags ... would it be 110.3(B) since I am assuming the transformers are not listed/labeled to be installed in a panel?
It seems that 725.55(D) would supercede 300.3(C)(1) per 90.3 and 725.1 ... also see the FPN under 300.3(C)(1) and 725.1
As long as the existing low voltage wiring complies with 725.55(D) I don't see a clear code violation. Am I missing something here?
Re: Doorbell Transformer in Panel
Only conductors & Circuit breakers and the equipment that the panel manufacturer put inside the enclosure are listed for use in that enclosure. If a doorbell transformer were to be used in the breaker panel it would have to be listed for such use. and listed on the panel label. also door bell transformers have open screws that are not insulated when you skin the low voltage wires you are not insulated to the maximum voltage. the transformers have hubs to mount the transformers, if you are setting it in the panel, it is not grounded.
Only conductors & Circuit breakers and the equipment that the panel manufacturer put inside the enclosure are listed for use in that enclosure. If a doorbell transformer were to be used in the breaker panel it would have to be listed for such use. and listed on the panel label. also door bell transformers have open screws that are not insulated when you skin the low voltage wires you are not insulated to the maximum voltage. the transformers have hubs to mount the transformers, if you are setting it in the panel, it is not grounded.
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: Doorbell Transformer in Panel
Many of the older transformers did not have a hub.
How can we legaly force a upgrade on something that say 40 years ago was common practice and excepted? I am 100% for tagging this in any new service and there has already been stated several codes that back this up.
Many of the older transformers did not have a hub.
How can we legaly force a upgrade on something that say 40 years ago was common practice and excepted? I am 100% for tagging this in any new service and there has already been stated several codes that back this up.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Doorbell Transformer in Panel
Jim
Would you want your car mechanic to install non-listed brakes on your old car when having a brake job installed?
For a service upgrade, when estimating the site, tell the customer that upon visual inspection that the bell transformer will need to be replaced at $ amount, that is not too difficult.
Pierre
Jim
Would you want your car mechanic to install non-listed brakes on your old car when having a brake job installed?
For a service upgrade, when estimating the site, tell the customer that upon visual inspection that the bell transformer will need to be replaced at $ amount, that is not too difficult.
Pierre
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