wrote in message
...
On Sat, 21 Mar 2009 17:43:24 -0400, "RBM" wrote:


"Tony Hwang" wrote in message
...
RBM wrote:
Just note where the wires of the existing transformer are attached and
connect the new one the same. Make sure your wire nut connections are
tight
"Bill Green" wrote in message
m...
I need to replace the transformer for my door bell and I have some
questions
on good wiring practices.

The existing (defective) transformer is attached to a metal junction
box
in
the middle of a cable whose primary duty seems to be providing power
to
the
furnace fan motor. There is also a porcelain light bulb socket
(luminaire
seems too fancy a word for this fixture) attached directly to the
'broad'
face of the junction box. This house is 40 years old so who knows
what's
been done around the wiring, I've had surprises before.

I expect that when I lock out the breaker and open the junction box
there
will be 4 black wires on one wire nut (1 black wire coming in, 1 black
wire
going out, 1 black wire for the luminaire, and 1 black wire to
existing
transformer), 4 white wires on another wire nut (similar distribution
as
for
black wires), and 3 grounds on a third wire nut (same as before except
that
the porcelain luminaire likely isn't grounded) or else attached to the
metal
box.

Is this a realistic assumption for a properly designed connection?

The reason I ask is that I had a another set of assumptions for a
similar
junction box that was on a switched circuit. Here the reality didn't
match
my preconceived notions; instead the white wire from the bathroom
ventilator
fan was attached to a sloppy-looking birds nest of ground wires; and
that's
the only way it would work.

Also, is it all right to connect 4 wires with one wire nut?
Information
from
Ideal shows UL listed wire combinations for number/size of conductors
for
each model number of Wire-Nut(R), so presumably this is okay. But is
this
commonly done as good practice and relatively safe? Would it be better
to
pigtail off so that I have 3 conductors under one wire nut with the
pigtail
connecting the existing light and the replacement transformer with
another
wire nut?

thanks!




Hi,
First, turn off 120V going to the x-former. I'd buy a heavy duty
x-former
which will last longer. It is just s step down x-former
120V AC to 24V AC.

I don't know where you retrieved this old post from, but, if it's a bell
transformer, it isn't 24 volt, and if it is 24 volt, it would probably be
for the heating system, but certainly not the doorbell

SOME doorbells use 24 volts. Most are 18?

Most chimes are 16, bells and buzzers are 6-8. I've never seen a 24, but
maybe up in your neck of the woods