Replacing dial thermostat with digital programmable one - can I do this myself?

[TheGMF]

I want to replace my old analogue thermostat with my shiny new Honeywell CM907. I thought it would a be a simple job that I could do myself but now I'm not so sure. I have three wires in the old thermostat and I only need two in the new one, as the earth (striped) is not needed. I understand the earth wire needs to be 'made safe' but I'm not sure how to do this.

Should I even be attempting this myself or is it a job for an electrician?

TIA

DH has done a few. But he can't remember them having earths.
I think if you get the green and yellow insulating tape and wrap it securely then that's ok.

don't use tape, as it unravels in time. It is vitally important that the earthwire cannot touch any of the other terminals. it must not go into terminal A, B or C.

In the backbox, you may see a parking terminal with a screw to hold the earth wire. If not, you can either buy a plastic "chocolate block" connector and cut off one of the blocks (you will understand this when you see it) and secure the wire inside that, or slide G&Y sheathing over the wire so that it is longer than the exposed end, then bend the wire back on itself like a hairpin.

You must turn off the electrical supply to the boiler and test for dead, because the terminals in your picture carry mains voltage.

chocblock

G&Y sheathing but your local hardware shop will sell you a little packet of half a metre or so for the same price.

I stand corrected. DH did say he'd use a choc block but I wasn't sure I could correctly get it across what that was on my phone.