Page 516 - IRSEM_Main Book

(j) FRP or insulated ladders arrangement shall be used to carry wires from
rack to rack or from other equipment.

(k) All entries to Electronic Interlocking room shall be suitably sealed to
prevent entry of rodents, lizards, insects etc.

(l) Electrostatic Floor Pads and Hand bands shall be provided near electronic
equipment to prevent damages to electronic equipment due to electrostatic
discharges.

(m) The room where Electronic Interlocking is installed shall be provided with
Air-conditioning.

(n) The building/room where E.I is installed shall be protected by External
Lightning protection arrangement at the top of building. In case there is
any other metallic earthed structure is available nearby which protects the
E.I building, then separate Class A at top of E.I room is not required. The
guidelines in National Building Code of India (2016 or latest) shall be
followed for calculations.

(o) Surge and lightning protection devices of appropriate class and rating shall
be provided for the regulated power lines before extending them to
Electronic Equipment Room. All equipment in Electronic Equipment Room
shall derive power from these regulated and protected power lines (clean),
but not from electrical service lines (dirty) used for room lighting air-
conditioning or fans.

(p) Clean and dirty wiring shall be clearly segregated and routed in different
enclosures/ladders, and where this is not feasible, a minimum distance of
150mm between clean and dirty wiring shall be maintained.

(q) If clean and dirty wiring need to cross at any place, then wiring should be
arranged at perpendicular to each other.

(r) Indicative type surge protection devices of appropriate class and rating
shall be installed for all copper based external interface ports (power,
communication, maintenance terminal, control panel interface etc).

(s) The connectivity between E.I and sub-systems like Control Terminal,
Control Panel, and Object Controller shall be planned with OFC cable to
avoid damage due to surge and lightning. The OFC shall be provided in
redundant manner to avoid failure due to cut/damage in one location/path.

21.5.2 Testing of Electronic Interlocking

(a) For Electronic Interlocking, the integrity of interlocking inside E.I designed
for a specific station can be tested at factory which is termed as Factory
Acceptance Test (FAT). This interlocking when installed at site and
interface wiring is connected then the test carried out as laid down for relay
interlocking, it is termed as Site Acceptance Test (SAT).

Chapter 21: Relay & Electronic Interlocking Page 459 of 535