lozarus
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Afternoon - despite a recent 18th edition pass (all but one right!) I'm having a bit of a moment whilst planning some upcoming works at our site. In reality I should wait, go home, refer to the big book and go from there. But it's playing on my mind and I can be a bit impatient. Also, I guess there may be a bit of a conversation here about existing circuits?
Situation is as thus - need to provide a spur for sign installers to install a backlit sign - all 24v LED stuff - Class 2 transformer, connected to switched fused spur.
Unbelievably (but not altogether unexpectedly), when checking how the land lay, I found a live but unused spur floating around above the suspended ceiling - an old Ashley thing, complete with smashed backbox and a bit of tape on saying "Live" (this isn't unusual in an ex-public building that has had 60 years of various companies and sub-sub-subcontractors doing reactive 'maintenance' classed works with no real records left).
So, traced the FCU - fed in old colour FP200 from a mid 90's Federal board on its own B16 - old plans indicate it used to feed a former Fire Alarm system before it was decommissioned and replaced/relocated 20 years ago. No other appliances on circuit. Zs well within. IR not yet done.
So - do I need to protect any part of this circuit with an RCD? I deduce not, as its not a socket outlet upto 32a - its a fixed appliance. And the circuit itself already exists as installed.
My brain started going down this path because really, all I'm doing is connecting an appliance - the circuit itself is already in situ.
Appreciate there's options here and the obvious thing is to shove an RCD in- source an RCBO for the board; fit an RCD in a DIN enclosure; fit one of the much debated RCD spurs ....but does it really require one? (I can't really see the risk from the appliance perspective - it's more the fixed wiring - but as I say - that already exists).
Apologies for the musing of such a small thing - but just thought I'd throw it out there
Situation is as thus - need to provide a spur for sign installers to install a backlit sign - all 24v LED stuff - Class 2 transformer, connected to switched fused spur.
Unbelievably (but not altogether unexpectedly), when checking how the land lay, I found a live but unused spur floating around above the suspended ceiling - an old Ashley thing, complete with smashed backbox and a bit of tape on saying "Live" (this isn't unusual in an ex-public building that has had 60 years of various companies and sub-sub-subcontractors doing reactive 'maintenance' classed works with no real records left).
So, traced the FCU - fed in old colour FP200 from a mid 90's Federal board on its own B16 - old plans indicate it used to feed a former Fire Alarm system before it was decommissioned and replaced/relocated 20 years ago. No other appliances on circuit. Zs well within. IR not yet done.
So - do I need to protect any part of this circuit with an RCD? I deduce not, as its not a socket outlet upto 32a - its a fixed appliance. And the circuit itself already exists as installed.
My brain started going down this path because really, all I'm doing is connecting an appliance - the circuit itself is already in situ.
Appreciate there's options here and the obvious thing is to shove an RCD in- source an RCBO for the board; fit an RCD in a DIN enclosure; fit one of the much debated RCD spurs ....but does it really require one? (I can't really see the risk from the appliance perspective - it's more the fixed wiring - but as I say - that already exists).
Apologies for the musing of such a small thing - but just thought I'd throw it out there
