Replace Menvier M12 with Nest Protect installation

[Lchan]

Hi,
I am currently replacing 1 of 4 Menvier M12 with a Nest Protect and need some expert advice on the (old) wiring.

I have a Menvier M12 with the following wiring:
Black - 0v (neutral)
Red - 12v (live)
White/Green - tamper zone
Blue - zone (interconnect)
Yellow - fire

As per the Nest Protect instructions, I worked out the following:
Blue/interconnect - Terminal block
Red/live - matched with live wires in the Nest 230V AC
Black/neutral - matched with neutral wires in the Nest 230V AC

1. Which ones of the above are earth?
2. What do I do with the White/Green tamper zone wire?
3. What do I do with the Yellow - fire wire?

Thanks in advance,
LC

 

[buzzlightyear]

ring nest and arrange for installer to call .

 

[Dobes_88]

Maybe I'm reading this wrong but sounds as if you're trying to install a 230v device on existing intruder alarm cabling...?

 

[MJPD29]

This is not going to work whatsoever from the sounds of it

 

[DPG]

I would take note of post #3 before going any further. It does sound a bit like this is what you are intending. Could you clarify?

 

[Lchan]

thanks all for the quick response.

Yes the existing smoke alarm directly connects to security alarm system.

"The M12 is a low current industrial standard sensor which can operate either as an optical, opto/heat combined, rate of rise heat or fixed 77° heat sensor via the selection switches. It is suitable for direct connection to most security alarm control panels or for use with other 12V detection systems."

Will it work if I just connected terminal blocks to
White/Green - tamper zone and Yellow - fire wires?

 

[davesparks]

No, it won't work, the nest is a 230V device and needs a 230V feed from a suitable circuit.

 

[shaun1]

To clarify, the M12 is an add on to your burglar alarm, which will trigger an alarm via the burglar alarm system if there is a fire. It is powered by 12v DC (same as a car battery) and sends a signal down the alarm wire if it detects a fire. If you remove this sensor it will cause a fault on your alarm system.

The nest is an independent fire alarm which connects to your wifi network and an app on your phone, it also links wirelessly to other nest products. As stated above, it needs a 230v AC supply (uk mains voltage). The existing wiring will not be suitable to carry this voltage.

So options are;

Have the fire sensor properly removed from the alarm system, and then a new 230v supply for the nest installed in its place.

Leave the sensor and locate the nest somewhere else, and install a 230v supply in this location.

Change the nest protect for a battery powered version