fp200 earth

[brizospark]

in a 24v dc fire system, when using fp200 should the bare core be used as a earth?

 

[telectrix]

should be used , sleeved and connected to exposed conductive parts, e.g. conduit boxes, of the fire alarm system, and continuous throughout each zone/sounder circuit, marshalle in control panel and connected to the cpc of the mains feed to the panel.

 

[Deleted member 26818]

A lot will depend on whether it is SELV, or ELV.
SELV should not have exposed conductive-parts connected to earth.
With ELV, it will depend on whether the exposed conductive-parts could come into contact with LV.

 

[telectrix]

i have always understood fire alarm circuits are classed as PELV. wouldn't swear on it though. just that i've always seen the cpc and exposed conductive parts to be connected to earth

 

[Deleted member 26818]

If they are classed as PELV, then yes exposed conductive-parts should be earthed.
Though I do often wonder why?

 

[telectrix]

same thought has crossed my mind occasionally. maybe somebody with BS5839 can enlighten us.