Re: Installing dimmer switch in old house

On Jan 17, 10:59 am, pgcampbell <pgcampb...@xxxxxxxxx> wrote:
I want to install a dimmer switch to control the lighting in my dining
room.  My house was built in 1925.
There are two light switches connected to one workbox.  One light
switch controlls the light in my dining room. The second lightswitch
currently does not contol anything. At one time it probably contolled
the light in the kitchen but the kitchen was remodeled 50 years ago
and the lights in there are gone.

When I removed the faceplate to the workbox I found two wires inside.
They are not color coded.  One wire connected to the top of lightwitch
number one ( controllng my dining room light).  The second wire looped
around a copper screw at the bottom of lightswitch number one and then
continued on to lightswitch number 2 where it terminated.

How would I then install a dimmer to control the lighting in my dining
room?  I believe the top wire is hot.
The bottom wire to lightswitch number two...is that a grounding
wire...treated as a green wire?  Or is that
the second hot wire...treated as a black wire?

Hi Mr. Campbell,

I have been following the post and I think the consensus is it is
difficult to tell which way around the wiring is just from text
descriptions here.

If you feel confident doing it yourself here is what might work.

1) You need to find which wire is the hot wire and which is the
neutral. For this you need to buy some test equipment. A Volt Probe is
what you need. Like this:

http://us.fluke.com/usen/products/Fluke+1ACII+VoltAlert.htm?catalog_name=FlukeUnitedStates&Category=ELT(FlukeProducts)

Fluke 1AC-II / 1LAC-II VoltAlert

You can also get them from Home Depot, but maybe not this brand. What
this gadget does is it allows you to tell which wire is the Hot one,
the one with power, without having to make an electical connection. It
can test through insulation. Cost is about $US 14-$US 21.

2) Switch off the light.

3) Disconnect the power at you main breaker / or remove the main fuse
to the circuit.

4) Open up the wall switch by removing the face plate.

5) Switch the power back on at the man breaker / put back the main
fuse.

6) Note the circuit is now live so be careful. Place the probe near
each wire in turn. You do NOT have to make
contact with the wire mretal connectors, just place it near the wire.
The HOT / Power wire will make the VoltProbe beep.
Remember that wire. The other wire is then your Neutral wire.

7) Power down the circuit at the mains

8) Remove the light bulb that the circuit switches.

9) Power back up the circuit.

10) Check to see with your probe if your live wire is still live. If
it is, then you are in good shape (case A -- Switch switches the live
wire). If there is no power to that wire, this means the light bulb is
connected to the hot wire directly, and the switch is switiching the
neutral (case B, Switch is swithing the neutral).

11) If the switch is switching the neutral (case B) I would call in a
professional and rewire the circuit. Switiching a neutral is bad for a
number of safety reasons. (Stop here do not go onto step 12)

12) Power down the circuit.

13) Replace the switch with a dimmer of your choice. You need a single-
pole dimmer (as opposed to a 3-pole dimmer). The 3-pole ones will work
too but a more expensive, and you do nto need it in this application.

14) Put back the light bulbs

15) Put back the face plate.

16) Power up the circuit. You are done.

Hope this is useful.

Warmest regards, Mike.



.

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