How do I extend thermostat wire and RS232 wire?

[johnnynine]

I need to relocate a thermostat and have the additional wire needed but I am not sure of the ideal way to "join" the cable sections.

The wire seems too small to use a wiring nut and I'm not sure I trust those little crimping gadgets...? I think I can join the thermostat wire in the attic but the rs232 wire will be joined in the wall and plastered over so I want to make sure I get it right.

 

[pete_c]

Personally when doing anything similiar I solder the wires together; then use small heat shrink tubing for each individual wire; then a larger piece of heat shrink tubing for all of the wires.

 

[mustangcoupe]

I agree with pete, solder and shrink tube is the best way if you cant replace it with one solid length

 

[JeffCharger]

another option would be those little gel-filled joiners used on phone lines.

 

[sic0048]

another option would be those little gel-filled joiners used on phone lines.

That is exactly what I was going to suggest. Those phone line connectors are designed for this exact thing.

 

[JimS]

I would be somewhat hesitant to use the gel connectors unless you have used them before, the size of wire is what the connectors were designed for, etc. But I suppose the same would go for soldering if you hadn't done it before. Personally I would go with soldering and shrink tubing. Or go back to somewhere you will have long term access to and run the new wire from there.

 

[Sandpiper]

I agree that soldering will result in the most reliable connection, but another alternative is to use the B-connectors which are commonly called beanies. Use the jel filled kind and they will give a very reliable connection also.

 

[Steve]

You're strongest and most permanent connection will always be solder whether it it then covered with simple tape, shrink tube or even a beanie. Solder and heatshrink will be the strongest and neatest. The telco ScotchLok IDC Butt connectors mentioned are nice but they are only rated for 19-26AWG and your t-stat wire is probably 18 gauge so I wouldn't use them. Personally I don't like beanies and I would never use them anymore unless you at minimum twist wires together first. ScotchLoks are much better if used on the right gauge and type (solid/stranded). There are other connectors like inline bullet connectors, spades, etc but nothing will beat solder.

But I also would either run a new cable or try to make a tap/connection someplace that is accessible. I'm not sure about HVAC wiring and codes but it is against code to bury a 120v electrical wire connection in the wall. Also think about if you ever have a problem with the HVAC the repair guy may simply refuse to work on it or insist on rewiring if they knew there was a connection in the wall.