Security & Fire Protection Systems/PC1555MX Physical Removal


Hello, We purchased an 80 year old rental property that at some unknown time had an alarm system installed.  We have ripped out the door and motion sensors but have now found an old metal PC1555MX in it.  
Is there any possibility that this box is live? if so would I which of the wires is the electrical?
Thank you for your time.


There is always the possibility that a piece of equipment may be live, but there again, it may not be.....

It would be wise to check the terminals inside the PC1555MX panel using a Voltmeter to comfirm for certain. Looking inside the panel, identify the long terminal block at the bottom of the main board (this is the keybus). The very first 2 terminals (left-hand end as looking) labelled "AC" are the main 120VAC power inputs to the panel, which would normally be Black(Line, Single Phase) and White(Neutral) cables.

Also, be aware of the telephone connections on the 5 way terminal block on right-hand end labelled "RING" (Red), "TIP" (Green), "R-1" (Grey) and "T-1" (Brown) which may also still be live if connected to the telephony system @ 48VDC. Terminal "EGND" should just be a Ground Wire from the building's electrical circuit.

Obviously, if you find a voltage on the panel, you will need to locate and isolate the feed for this before conducting any further works, if removing completely, on the panel.


Security & Fire Protection Systems

All Answers

Answers by Expert:

Ask Experts


Malcolm Evans


I can answer questions relating to Fire systems and Gaseous Fire Suppression systems, both mechanical (including Integrity Testing) and electrical components (Addressable and Conventional systems) and can cover UK standards and regulations. Also, I am Ansul trained and certified in R-102 Ansul Kitchen Suppression system design, installation and maintenance.


I have 2 years experience with my current employer, a UK Fire Protection Company, in installation, testing and maintenance of various system types, and design of Ansul R-102 Kitchen Suppression systems.

FIA (Fire Industry Association) and BAFE (British Approvals for Fire Equipment) accredited. Ansul certified.

Secondary Education (GCSE's) and Technical College (City & Guilds).

Past/Present Clients
Land Rover; RBoS; Wilkinsons; Jaguar; British Telecoms; British Sky Broadcasting; Welsh Assembly; BBC Scotland; Crowne Plaza Hotel chain; Holiday Inn Hotel chain; Hilton Hotel chain; London Heathrow; Gatwick; Financial Institutions; Local Government Offices and many more

©2016 All rights reserved.