On Sat, 12 Jan 2013 09:15:49 +0000, Tim Watts
wrote:

On Friday 11 January 2013 22:15 wrote in alt.home.repair:

On Fri, 11 Jan 2013 15:07:52 -0600, Mark Storkamp
wrote:

In article ,
gary wrote:

I need electricity for a ceiling fan. In my attic, I found an existing
wire
that powers a light switch. I want to run a new wire from the existing
wire
to the ceiling fan. How do I tap into the existing wire?

The power may be running to the light, and the wire going to the switch
might only be a loop used to break the circuit to the light. If that's
the case then you can't tap into it there.
So tap into the light then. It's not rocket science either way. The
point is, it HAS to be done at a box. You can't "vampire" it - and the
box needs to be accessible.

Do we even know where the OP lives (ie which electrical regulations are in
effect)?

I agree that screw terminals, regulation or no regulation, need to be
accessible - screws can loosen over time.

However, local regulations *may* permit:

1) http://www.tlc-direct.co.uk/Products/ASJ804.html - spring loaded
"maintenance free" joints.

2) Crimps - done with a correct ratchet tool and not the piece of tin from
some car radio shop. Granted, not much help with a 3 way tap.

3) Soldered joints, insulated in heatshrink and boxed.

The British IET 17th Edition regulations permit all the above. I have no
idea about the US NEC, or canadian regs.

Soldered joints are an art though - the conductors should be mechanically
bound prior to soldering - eg ferrule or overlapped and a thin copper wire
used to lash them. It's not good enough to just blob them together.


Until very recently ALL of the above were forbifdden by american and
canadian code.
In some areas the "vampire" clips formerly allowed in mobile homes are
now also allowed in permanent residential installations - although I
would NEVER use them - even in a trailer.

Regarding where to tap:

I can't imagine the OP's jurisdiction has any more different ways of wiring
lighting than the UK. So...

Switch: May have a permanant live/hot. But no neutral.

Or may have both

Light fitting: May be used as a junction box so may have live/hot. neutral
and switched live/hot in which case it is possible.

Or it may just have switched live and neutral and the junction box with live
and neutral is somewhere else.

So the OP needs to possibly find the main feeder cable and joint into that?

Unlike UK "ring circuits" there is no "feeder" per se. All circuits
have "home runs" to the service panel, where they are protected by a
breaker (or in some cases , still) a fuse.

Does the fan require a ground/earth and is there one present in the lighting
circuit?

In all recent (last 40 years or so) north american installations the
ground is there and required.

================


Also - do local regulations permit fans running from lighting circuits? How
many amps does the fan take? It's probably OK, but the question needs
asking.
The fan draws less than most lights - and in all North American
codes lighting and ancilliary loads can be shared on the same circuit.