v
DANGER:
Important Plus
+
Considerations
To provide the most reliable operation, the Siemens ST950S Plus
+
controllers use a DC supply.
To maintain all street voltages within ELV limits, equipment outside the cabinet must
be supplied with voltages within the band 0 to +48V DC with respect to earth. Voltages
beyond that will result in overall voltages within the system being in excess of the ELV
limit as defined by BS7671.
Care should be taken to ensure that no LV (Mains Voltage) equipment is installed within the
ST950S Plus+ street furniture as this will result in risks to personnel and risk of catastrophic
failure of equipment.
The Siemens ST950S Plus
+
controller has been designed and proven to meet the following
requirements for Protective Extra Low Voltage (PELV) and the operation of a signal compliance
monitoring system with ELV voltages:
1) The Siemens ST950S Plus
+
system is PELV and the earth is connected all the way through,
as allowed for in BS7671 414.4.1. The source is a safety isolating PSU as allowed in BS7671
414.3 (iv). Protective Isolation within the controller cabinet is achieved between the PELV
circuits and those higher than band I by ALL conductors having insulation rated for the highest
voltage 250V, as mandated for in BS7671 414.4.2 (iii), and where the parts of the circuits are
not wires / conductors, then physical isolation as allowed for in BS7671 414.4.2 (v) may be
used.
Important:
Disposal
As with all modern equipment, there are a number of security artefacts that exist within the
hardware. When replacing equipment, the swapped-out CIC and Nodes must be disposed of in
a secure way.
