Restoring old doorbell and installing transformer.. need advice

Hi all, I have an old NuTone Door chime that looks very similar to the one in this link.
http://cbvfd.org/wp-content/uploads/...mes-canada.jpg

I'm going to be purchasing a Transformer and running wire to it and the front, rear door but am uncertain on a few things.

- Would this chime likely run off 24v 20a?
- Most transformers seem that they are intended to be surface mounted, would I mount one on a stud in my unfinished basement near a J-Box and then run romex from the J-Box to it? (i'm not fond of the idea of leaving exposed contacts)

 

Some runs off 16V and some runs off 24V.
Does your bell have any rating?
It probably will work fine on both since those door bells are just made with solenoids.

You mean 20VAC not 20A. Right?
20A transformer will big and heavy (unless it is a switching power supply) and definitely not for a doorbell.


Most door bell transformers are meant to be mounted on knockout of a metal junction box. It is mounted outside.
Transformers should not be mounted inside junction box because it can overheat. Also, low voltage and high voltage wiring should not be in a same junction box.

Exposed low voltage terminals are safe to touch and does not need to be covered.
If you like to hide them as much as possible, there are plug type transformers.

https://www.amazon.com/Class-II-Tran.../dp/B004VMVDTA

You hold it down to bottom receptacle of a duplex receptacle using screw.

 

A 16v 20va transformer is really what you want.

 

I can't find any sort of rating on the doorbell itself, There WAS a transformer downstairs but it got gutted during a recent remodel as it wasn't wired up to the low voltage side.

The Transformer was previously mounted to the outside of a junction box in an unfinished basement and looked kind of like this one. https://www.amazon.com/Honeywell-AT1...l++transformer

From the basement there was a cable that was ran to the chime upstairs and then one to the rear porch. Is this configuration fairly normal?

 

Yes. That is normal and how they are meant to be wired.

 

What's a good way to determine whether my chime needs 16 or 24v?

 

I'm pretty sure it will work on both, but 16V is probably safer bet since it is lower voltage and most door bells call for 16V.

 

In the old days 24vac was only for HVAC. 8 to 16 vac was for door chimes.

 

Ended up ordering this one as it's a name brand, has a good ampacity and can be thread mounted on the J-Box cover. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 Just to confirm though, these wires are tinned CU, NOT AL right? Will be using some 18GA jacketed thermostat wire to the bell and chime.

 

Yes.
Some Chinese off brands may use copper clad aluminum, but rare. NuTone will for copper for sure.

You can mount it on junction box cover with knock out hole or just mount on the side of junction box.

 

I'm definately going to use the knockout hole as I don't like exposed AC wiring when I can help it.

I'll then be running 18-2 thermostat wire to the doorbell and chime. I plan to butt splice the wiring, are there any specific rules for enclosing low voltage splices?

 

Low voltage splices don't require any enclosures. Just use a small blue or gray wirenuts.
You could crimp the splices as well, but there is no need for that and solid wires don't crimp well. Wirenuts will make better splice than other crimp splices unless you have a proper tool for crimping.