Help identifying neutral for exterior lights switch upgrade

Question

I bought a programmable timer switch for outside lighting in an older home (Canada). I peeked in the gang box so I could make this rudimentary drawing.

I have "X'd" out Switch 2 and Cable 3 as it is on different circuit. The new switch will replace Switch 3 for exterior lighting. It is a timer switch which requires a neutral, but no neutral is currently connected to Switch 3. Switches 1 and 3 are on the same circuit. Switch 1 is 1 of 2 switches controlling a kitchen light. Switch 2 is the sole switch of outside soffit lights. Neutral from Leads 1, 4 and 5 are pig-tailed via marette. Neutral line 2 is to Switch 1. Hot line 2 tapped to 'on terminal' of Switch 3 and continues to line 1.

Can I replace Switch 3 with a new programmable switch and tie it to grouped neutrals (1, 4 & 5) or just connect it to neutral 4?

Answer 1

Excellent diagram! To sum it up:

• Cable 1 provides power to switch switches 1 (via a 3-way in another box) and 3 and provides neutral to kitchen and exterior lights.
• Cable 2 is a 3-way switch cable for kitchen lights. It has red and white travelers and black always hot.
• Cable 4 carries switched hot black from the kitchen 3-way switch and neutral from cable 1 to the kitchen lights.
• Cable 5 carries switched hot black from switch 3 and neutral from cable 1 to the exterior lights.

A "dumb" switch doesn't use neutral, which is why switch 3 doesn't connect to it right now. But you are all set to add it:

• The two hot black wires from the upper left connection on switch 3 connect to the Line connection on the new switch. Depending on the type of connection, you will likely need a wire nut (Marrette).
• The switched hot black wire from the lower left connection on switch 3 connects to the Load connection on the new switch.
• Add the neutral wire for the new switch (you may need to get a piece of white wire (14 AWG or 12 AWG for a 15A circuit, 12 AWG for a 20A circuit) if the new switch has screw terminals) to the combined 1, 4, 5 white neutral wires. You may need a new wire nut if the old one is too small or does not hold securely - it will have 4 wires at the end: 1, 4, 5, switch 3.
• If the switch has a ground wire, add it to the group of grounds. If the existing grounds are screwed in (diagram implies that, but I'm not 100% sure) to the back of a metal box then you have a grounded metal box and the switch will normally ground automagically to the box through the yoke, provided it has a metal yoke.