Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 12 Page 67 of 265
 Common return cable for all BUT green aspect: 24W (6W+18W) at
180 metres = 3 cores
 Green aspect return cable 12W at 180metres = 2 cores
4. If required to minimise core usage it is permissible to common signal returns
on the same pole as long as the total lamp load dependent on that return is
considered and the cable length limitations defined in the table are observed.
For example, two 12W RAG traffic signal heads require that a load of 24W is
considered with a common return cable. (Note: please also consider the
comments given in paragraph 1)
5. Regulatory signs should normally be cabled with a separate drive and return
core.
Where more than one regulatory sign is fitted to a pole, the drive and return
for these may be common, as long as total load dependent on those cables is
considered and the cable length limitations defined in the table are observed.
If required to minimise core usage it is permissible to common regulatory sign
and traffic signal returns on the same pole as long as the total load
dependent on that return is considered and the cable length limitations
defined in the table are observed.
Example, assuming a distance of 100 metres using 1.0mm
2
cable:
 Reg Sign supply cable: 7W at 100 metres = 1 core
 RAG traffic signal drive cables: 12W at 100 metres = 1 core each (x3)
 RA + Reg Sign Common return cable: 19W (12W+7W) at 100 metres
= 1 core.
 Green return cable: 12W at 100metres = 1 core
It should be noted from looking at the table that above 100 metres, 2 cores
would be required for the 19W common return, and above 160 metres, 2
cores would also be required for each 12W signal drive cable.
6. Tactile units are to be provided with a separate drive and return core. Tactile
units driven from the same phase green LSLS output can share a common
drive and return core. For the purposes of assessing acceptable cable run