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Trying to replace my doorbell transformer

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  • Nov 7th, 2020 10:03 am
[OP]
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Dec 1, 2018
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Trying to replace my doorbell transformer

I recently bought a video doorbell and it looks like I need to upgrade my transformer for it to function properly. Thought it would be a simple task but it looks like my old transformer doesn't have a ground (green) wire whereas my new one does. I live in a condo townhouse and this is my breaker box.

Based on my research, I can connect the black/white wires of my new transformer the same way my old transformer has done it. However, I've read conflicting material as to whether the green wire should be connected to the left bar (which I believe is the ground bar) or if it can also go to the same bar as the white wire (the neutral bar?).

Any advice appreciated. What are the risks if I wire my doorbell transformer's ground wire incorrectly?
19 replies
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Get a continuity tester just to be sure if you want but the bar on the left should be thd ground bar. If the incoming wires with ground have their ground wires attached there (appears to), then it is where to ground to.
I smile when I see container ships sailing past my house laden with stuff made in China
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pfc456 wrote: Sorry thought I included it. Attached here.
Green goes to the grounding bar on the far left were all the bare ground wires are connected to

The metal case of the transformer is mechanically tied to the breaker panel case/ ground
[OP]
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Dec 1, 2018
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l69norm wrote: Green goes to the grounding bar on the far left were all the bare ground wires are connected to

The metal case of the transformer is mechanically tied to the breaker panel case/ ground
Thanks. I'm sharing another photo below - it looks like I have two grounding bars (one on the left and one on the right). Is that normal?

Out of curiosity, what's the most dangerous thing that can happen if I install the grounding wire incorrectly (i.e. if that bar is actually a neutral bar, or if the bar on the far left isn't actually a grounding bar)?

Is turning off the breaker for the live wire connected to my doorbell sufficient or do I need to turn off the power for my entire house (might be a stupid question but just want to make sure).
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  • wiring_2.jpeg
Last edited by pfc456 on Nov 6th, 2020 6:14 pm, edited 1 time in total.
[OP]
Newbie
Dec 1, 2018
18 posts
thriftshopper wrote: Get a continuity tester just to be sure if you want but the bar on the left should be thd ground bar. If the incoming wires with ground have their ground wires attached there (appears to), then it is where to ground to.
Thanks. I just shared a more clearer photo above. It looks like my box has two ground bars - is that normal?

Also how would I use the continuity tester? in this scenario? I have a voltmeter but I'm guessing it doesn't help here.

What's the most dangerous thing that can happen if I install the grounding wire incorrectly?
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Feb 11, 2018
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pfc456 wrote: Thanks. I'm sharing another photo below - it looks like I have two grounding bars (one on the left and one on the right). Is that normal?

Out of curiosity, what's the most dangerous thing that can happen if I install the grounding wire incorrectly (i.e. if that bar is actually a neutral bar, or if the bar on the far left isn't actually a grounding bar)?

Is turning off the breaker for the live wire connected to my doorbell sufficient or do I need to turn off the power for my entire house (might be a stupid question but just want to make sure).
Yes you have two ground bars, one for each leg (side). If you have never worked in an electric panel I would strongly suggest you turn off the main (house) breaker. Your safety is what matters the most. Make sure to have a flashlight before turning off the main, it's dark out there without power ;)
What you keep in your heart will take you further than what you keep in your pocket.
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I'd strongly suggest turning off all power too.
I smile when I see container ships sailing past my house laden with stuff made in China
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Mar 23, 2008
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pfc456 wrote: Thanks. I'm sharing another photo below - it looks like I have two grounding bars (one on the left and one on the right). Is that normal?

Out of curiosity, what's the most dangerous thing that can happen if I install the grounding wire incorrectly (i.e. if that bar is actually a neutral bar, or if the bar on the far left isn't actually a grounding bar)?

Is turning off the breaker for the live wire connected to my doorbell sufficient or do I need to turn off the power for my entire house (might be a stupid question but just want to make sure).
Jebus, dude! Unless you know what the heck you're doing, you should NEVER muck around in the panel without the power turned off! One slipped screwdriver and you're in for a world of hurt. If you're lucky.

C
[OP]
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Dec 1, 2018
18 posts
TomLafinsky wrote: Yes you have two ground bars, one for each leg (side). If you have never worked in an electric panel I would strongly suggest you turn off the main (house) breaker. Your safety is what matters the most. Make sure to have a flashlight before turning off the main, it's dark out there without power ;)
CNeufeld wrote: Jebus, dude! Unless you know what the heck you're doing, you should NEVER muck around in the panel without the power turned off! One slipped screwdriver and you're in for a world of hurt. If you're lucky.

C
Thank you all for the feedback. I will definitely turn off the main power for the breaker! I'll validate that all wires that I can touch are off with a voltmeter before attempting anything.

For this one particular switch, it looks like it's powering my doorbell + something else in my house (hence the two black wires connected to the same screw). Is there any concern switching to a more powerful transformer may be too much load for this switch? I presume that the breaker would trigger in that scenario.
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pfc456 wrote: Thank you all for the feedback. I will definitely turn off the main power for the breaker! I'll validate that all wires that I can touch are off with a voltmeter before attempting anything.

For this one particular switch, it looks like it's powering my doorbell + something else in my house (hence the two black wires connected to the same screw). Is there any concern switching to a more powerful transformer may be too much load for this switch? I presume that the breaker would trigger in that scenario.
Anything is possible, but not likely with just a transformer change. And yes, the breaker would trip in that case.

Do you have two wires coming off the transformer, going to two different locations? Do you have a front and back doorbell? Or are you talking about the two wires coming off the one breaker? Maybe one of the electricians in this forum can comment on whether that's acceptable from a code perspective.

C
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pfc456 wrote: Thank you all for the feedback. I will definitely turn off the main power for the breaker! I'll validate that all wires that I can touch are off with a voltmeter before attempting anything.

For this one particular switch, it looks like it's powering my doorbell + something else in my house (hence the two black wires connected to the same screw). Is there any concern switching to a more powerful transformer may be too much load for this switch? I presume that the breaker would trigger in that scenario.
Doorbells need a ridiculously small amount of amps, don't worry about it. If you look at both transformers it might even be written on them.
What you keep in your heart will take you further than what you keep in your pocket.
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CNeufeld wrote: .
Do you have two wires coming off the transformer, going to two different locations? Do you have a front and back doorbell? Or are you talking about the two wires coming off the one breaker? Maybe one of the electricians in this forum can comment on whether that's acceptable from a code perspective.
.
Technically, no - you are not allowed to double tap from 1 breaker unless the breaker was designed to accommodate this

Image

it's a lot harder to get the right pressure on the connection in a double tap so that it won't come loose
[OP]
Newbie
Dec 1, 2018
18 posts
CNeufeld wrote: Anything is possible, but not likely with just a transformer change. And yes, the breaker would trip in that case.

Do you have two wires coming off the transformer, going to two different locations? Do you have a front and back doorbell? Or are you talking about the two wires coming off the one breaker? Maybe one of the electricians in this forum can comment on whether that's acceptable from a code perspective.

C
l69norm wrote: Technically, no - you are not allowed to double tap from 1 breaker unless the breaker was designed to accommodate this

it's a lot harder to get the right pressure on the connection so that it won't come loose
I'm swapping a really old 5VAC transformer in exchange for a 16VAC-10VA transformer so I can use my Ring Video Doorbell Pro. I've also seen silver-coloured wires connected to the ground bar. Out of curiosity what kind of wires are these? Since my house was built in the 70s, could it be aluminum wiring?
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pfc456 wrote: I'm swapping a really old 5VAC transformer in exchange for a 16VAC-10VA transformer so I can use my Ring Video Doorbell Pro. I've also seen silver-coloured wires connected to the ground bar. Out of curiosity what kind of wires are these? Since my house was built in the 70s, could it be aluminum wiring?
Yes, likely aluminium
[OP]
Newbie
Dec 1, 2018
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l69norm wrote: Technically, no - you are not allowed to double tap from 1 breaker unless the breaker was designed to accommodate this

Image

it's a lot harder to get the right pressure on the connection in a double tap so that it won't come loose
Gotcha, so whoever previously did the work may have done it incorrectly. If I move forward with replacing the transformer can I tighten the screw and pull on both black wires to verify they can't easily come loose?
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pfc456 wrote: Gotcha, so whoever previously did the work may have done it incorrectly. If I move forward with replacing the transformer can I tighten the screw and pull on both black wires to verify they can't easily come loose?
Yes after switching off the main breaker you can 'play' with the wires. If the two wires are next to each other in the same hole it is a somewhat better fit than one on top of the other. Anyway screw hard enough and nothing will move.
What you keep in your heart will take you further than what you keep in your pocket.
[OP]
Newbie
Dec 1, 2018
18 posts
TomLafinsky wrote: Yes after switching off the main breaker you can 'play' with the wires. If the two wires are next to each other in the same hole it is a somewhat better fit than one on top of the other. Anyway screw hard enough and nothing will move.
Thank you so much! So I'll go through these order of steps this weekend:

1) Turn off main power
2) Verify no power in any of the black wires in my breaker box with my voltmeter
3) Unscrew the screws holding onto the black/white wire for the old transformer, remove old transformer
4) Connect white/black wire of my new doorbell transformer to the same connections as the old transformer, tighten screws. Tug on each wire to make sure they're secure
5) Connect the green wire to the ground bar on the top left (any of the unused holes should do?). Tighten screw to secure the wire. Tug on the green wire to ensure it's secure.
6) Turn the main power switch to the breaker back on. Verify everything works as expected and existing doorbell still works
7) Replace old doorbell with my Ring Video Doorbell Pro
Deal Addict
Feb 11, 2018
1688 posts
1348 upvotes
pfc456 wrote: Thank you so much! So I'll go through these order of steps this weekend:

1) Turn off main power
2) Verify no power in any of the black wires in my breaker box with my voltmeter
3) Unscrew the screws holding onto the black/white wire for the old transformer, remove old transformer
4) Connect white/black wire of my new doorbell transformer to the same connections as the old transformer, tighten screws. Tug on each wire to make sure they're secure
5) Connect the green wire to the ground bar on the top left (any of the unused holes should do?). Tighten screw to secure the wire. Tug on the green wire to ensure it's secure.
6) Turn the main power switch to the breaker back on. Verify everything works as expected and existing doorbell still works
7) Replace old doorbell with my Ring Video Doorbell Pro
Yep, you got that right! Let us know everything is working fine after you are done.
What you keep in your heart will take you further than what you keep in your pocket.

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