Maximum spur length for FISCO devices?

[prachides]

Hi,

can somebody help me with limitation on spur length in case of FISCO devices?
I have come across with 2 figures of 30m and 60m while going thr some litrature on net.
my plant area is Zone1, IIB, T3.
Power supply current=120mA

[chriss]

Hello,

the current valid value for Fisco spur legths is 60m. This is stated in the IEC 60079-27 which was published in 2002. The old value of 30m was valid before this standard was published.

[prachides]

Thanks Chriss.

Prachi

[Mike ONeill]

The reduction on permissible spur length is one of the restrictions that comes with the adoption of FISCO, the other one being the overall reduction in total cable to 1000m (the 100-fold reduction in MTBF is a consequence of the design concept used, rather than a reduction required by the specification). 60m as the maximum spur length is now published as the maximum length, but 30m is part of older literature/specifications still doing the rounds