Joining alarm cable behind plaster

[andusbeckus]

I have an new bay window and now the existing magnetic connectors for the alarm are too short to reach the window. The alarm wire needs extending but where the joint would be is going to be plastered over.

Is there any acceptable way of joining the cables behind plaster without having to pull it out and put a new piece in?

 

[lamb]

Jelly crimps

 

[alarm man]

solder will give you a better joint,then either heat shrink or tape the joint

 

[andusbeckus]

solder will give you a better joint,then either heat shrink or tape the joint

went for this option as it was less bulky and cheaper. Thanks for the advice