Siemens ST950 Plus+ User Manual page 5

ST950 Plus+ User Manual
Important Plus
To provide the most reliable operation, the Siemens ST950 Plus
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 ST950 Plus+
street furniture as this will result in risks to personnel and risk of catastrophic failure of equipment.
The Siemens ST950 Plus
+
for Protective Extra Low Voltage (PELV) and the operation of a signal compliance monitoring system
with ELV voltages:
1) The Siemens ST950 Plus
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.
Disposal
As will 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.
ST950 Plus+ User Manual
+
Considerations
controller has been designed and proven to meet the following requirements
system is PELV and the earth is connected all the way through, as allowed
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667/HE/53000/000
controllers use a DC supply.
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Issue 2
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