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BS5839-6 grade D 240v supply
#1
Guys
Any chance someone could help me out, I'm working away from home and don't have my copy of the regs to hand.
Could somebody confirm what BS5839-6 says about Grade D detection connected to a 240v supply controlled by a pre-pay meter.
cheers in advance
Any views expressed are that of my own not my company!Exclamation
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#2
is it an HMO?


15.5 Recommendations for power supplies for Grade D systems
The following recommendations are applicable.
a) The normal supply for smoke alarms and any heat alarms in a Grade D system should be derived from the public electricity supply to the premises. The mains supply to the smoke alarms and heat alarms should take the form of either:
i) an independent circuit at the premises’ main distribution board, in which case no other electrical equipment should be connected to this circuit (other than a dedicated monitoring device installed to indicate failure of the mains supply to the smoke alarms and any heat alarms);
or
ii) a separately electrically protected, regularly used local lighting circuit in which case there should be a means for isolation of the smoke alarm(s) from the lighting circuit (e.g. for maintenance).

NOTE 1 This does not imply that there need be separate electrical protection of the smoke alarm circuit; a single means of protection against overload or short circuit (e.g. a fuse or miniature circuit breaker) serving the entire circuit is acceptable.
NOTE 2 A number of manufacturers use a fixed base for the electrical connections, and the smoke or heat alarm can be readily removed by use of a tool operated release tab, etc.

b) Any isolating device that isolates the power supply to the smoke alarm(s) should be labelled “SMOKE ALARMS: DO NOT ISOLATE”. Where smoke alarms are connected to a lighting circuit, the label should, instead read “CAUTION. SMOKE ALARMS CONNECTED TO THIS CIRCUIT. DO NOT UNNECESSARILY ISOLATE”.
c) If smoke alarms and any heat alarms are of a type that can be interconnected by wiring, all smoke alarms and heat alarms should be connected on a single final circuit.
NOTE 3 This recommendation is intended to ensure electrical safety by avoidance of a situation in which one device, isolated for maintenance, remains connected to a live device via the interconnect wiring. Accordingly, the recommendation does not apply if the form of interconnection is not capable of conducting current, e.g. if the means of interconnection comprises radio communication rather than wiring.
d) The standby supply for smoke alarms and heat alarms may take the form of a primary battery, a secondary battery or a capacitor.
e) The capacity of the standby supply should be sufficient to power the smoke alarm(s) and any heat alarms in the quiescent mode for at least 72 h whilst giving an audible or visual warning of power supply failure, after which there should remain sufficient capacity to provide a fire warning for a further four minutes, in the absence of a fire, a fault warning for at least 24 h.
f) In a house in multiple occupation with a single key or card-operated meter, the mains power supply for all smoke and heat alarms may be served by the meter. However, where, in a house in multiple occupation, the accommodation of each resident is served by a separate key or card-operated meter, Grade D smoke and heat alarms in common parts should not be supplied via the meter of any resident.
NOTE 4 This is to prevent isolation of the power supply to devices in common parts when, for example, the accommodation of one resident is vacated for a prolonged period of time.
g) In a house in multiple occupation with a permanent landlord’s supply in the common parts, but prepayment meters in dwelling units, a supply to any smoke alarms in the dwelling units should be derived from the landlord’s permanent supply in the common parts. Where this applies, permanent notices should be displayed on or adjacent to the meter, as well as on or adjacent to any secondary consumer unit in the dwelling, which states:
“CAUTION. SMOKE ALARMS ARE NOT CONNECTED TO THIS CIRCUIT. ISOLATION/ SWITCHING TO OFF AT THIS POINT, OR HAVING NO CREDIT ON THE METER, DOES NOT ISOLATE THE ELECTRICAL SUPPLY TO THE SMOKE
ALARM.”
www.fia.uk.com

Technical Manager FIA

All comments and views are mine own and may not reflect the views of FIA
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#3
Will
Many thanks
Any views expressed are that of my own not my company!Exclamation
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