Bonding and Earthing for Railway Electrification

1. CHECK LIST FOR OHE BONDING AND EARTHING FOR INDIAN RAILWAY
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1) Check Structure bond on all type of masts and up rights of OHE
2) Check Longitudinal bond on fish plate joints of rails on all non-track circuited area
3) Check Cross bond-between rails (open route 3 per KM in non-track circuited area)
4) Check Cross bond between track on double line and yards ( negative rails in track
circuited area)
5) Check Z bonding at insulated rail joint for staggering of polarity for DC track circuited
area
6) Check “U’’ Bond (check / guard rails in bridges)
7) Check bonding for girders of ROB
8) Check bonding for FOB
9) Check bonding for Passengers Shelters in platforms provide proper embedding of
bond on platforms and ensure cleat on coping of platform
10) Check bonding metal fencing
11) Check in major bridge for every 100 m hand rails to be connected to track by bond
12) Check at tunnel for earth wire to run through out
13) Check bond for metal pipeline along track if any
14) Check at Level crossings All the traction rails shall be provided with cross-bonds at only
one location which shall be within five metres from either of the transverse edges
(non-track circuited)
15) Check the Level crossing A frame, Lifting barrier base , lever mechanism provided with
bond.
16) Check PTFE neutral section connected with structure and earthed
17) Check earthing for girders of ROB, FOB and bridge ( both side)
18) Check Isolator at siding line provided with earthing heel and earth ,all Isolator(SS/SM)
handle provided with copper flexible bride with structure
19) Check Passenger shelters / metal fencing / any structure at stations / near/along track
- More than 20 m to 350 m –Bond , more than 350 m are earthed .
20) Check bonding in track circuit area earthing done every 100 m up to and beyond 50 m
of home signal on both side.
21) Check earth electrode are connected to girders of ROB, FOB , bridges, fencing,
platform shelters, sheds, neutral section, Isolator, yard etc. and also connected to
nearest traction rails by means of two distinctive connection
22) in addition to connection to the relevant structures/equipment etc.,
23) Check the bond for Painting ( Finish with double coat bituminous black paint)
24) Check the Size of MS bond is 40 X 6 mm and Bolt GI - M 16 – 50/38 , Flat washer,
spring washer, nut etc.,
25) Check in track circuited area bond placed below the ballast 150-200 mm and
provided with 2 -3 mm PVC sleeve to avoid contact with positive rail / triple
insulation if required
26) Check for tightness of bolt between 160 – 213 Nm
27) Check No sharp edges and bolted joints on bond
28) Check bolting edge of bond should butt /flush with mast properly / rail (bent properly)
29) Check the holes drilled on neural axis on the traction rail ( Use template)
30) For 60 kg Rail.80.95mm from bottom flange and 91.05mm from Rail head
31) For 52 kg Rail.75.59mm from bottom flange and 80.41mm from Rail head
32) Hole to be chamfered by suitable compression die

2. CHECK LIST FOR OHE BONDING AND EARTHING FOR INDIAN RAILWAY
2 | P a g e
In case of any doubt or corrections please mail to : v.gopal21@gmail.com
33) No Hole to be drilled 250 mm close to Fishplate, 170 mm to existing hole and 100 to
al. thermic welding/ FB welding
34) Check the bond is made as per the shape shown in RDSO drawing
35) Check that no bond is connected in signal ( Positive Rail) in track circuited area
36) TSS/SWS/FP
Check that all the traction rails shall be provided with rail bonds for a distance of 1000m
on both sides opposite to the FP and all the traction rails are cross bonded at a distance
of 300m, 500m, 750m & 1000m on both sides of the FP.
Check the earth electrodes provided at switching station shall be interconnected to
form a closed loop to form earthing ring. This ring, traction rail and the earth mat are
connected by means of two distinct connections of 50 mm x 6 mm MS flat
Check the designated terminal of the secondary of each potential, current and auxiliary
transformer , masts, structures, fencing uprights, and all outdoor equipment pedestals
including auxiliary transformer tank are connected to the earthing ring by means of two
separate and distinct connections and the metal casing of potential and current
transformers are connected to the mast/ structures by means of two separate and
distinct connections made with 50 mm x 6 mm MS flat
Check all fencing panels , metallic door panels and upright are connected to the
supporting uprights by two separate and distinct connections with 6 SWG G.I. wire.
Check the ground terminal of lightning arrester are connected directly to the earth
grid/ring by means of two separate and distinct connections made with 50 mm x 6 mm
MS flat earthing leads from the lightning arrester are brought to the earth grid/ring by
as short and straight path as possible
Check the metal casing of LT AC. and DC. distribution board, battery chargers, terminal
board, remote control equipment cabinets and other such equipment are connected to
the earthing ring by means of two separate and distinct connections made with 8 SWG
G.I. wire.
Check at TSS and SWS where power supply at 415 V/ 240 V, ac, 50 Hz, is taken from the
local supply authority and having neutral earth at some distant point in the premises of
the supply authority, the neutral of such supply are earthed by means of two separate
and distinct connections made with 6 SWG G.I. wire by connecting to an independent
earth electrode.
Check 52 kg/m rail with length of 13 m shall be buried near the track at the TSS /SWS
at a depth of one metre. Two separate and distinct connections shall be made the
earthing grid and the buried rail. The buried rail to be connected by means of two
separate and distinct connections made to the traction rail with 75 mm X 8 mm MS flat
Check when the FP is located separately away from the traction TSS, the buried rail
provided at the FP (where one terminal of the secondary winding of the traction power
transformer of the substation is grounded).One terminal of the secondary winding (25
kV winding) of each traction power transformer to be earthed directly by connecting it
to the earthing grid and to the buried rail by 75 mm x 8 mm MS flat.
Check the designated terminal of the secondary of each potential, current and auxiliary
transformer are connected to the earthing grid by means of two separate and distinct
earth connections and metallic frame work of all outdoor equipment such as
transformers, circuit breakers, interrupters and isolators, as well as steel structures are
connected to the earthing grid by means of two separate and distinct connections

3. CHECK LIST FOR OHE BONDING AND EARTHING FOR INDIAN RAILWAY
3 | P a g e
In case of any doubt or corrections please mail to : v.gopal21@gmail.com
37) Check Various size of flats and wires used at respective location
40 X 6 mm MS – OHE bonding and earthing
50 X 6 mm MS -25 kV System and equipment earthing in TSS and SWS including AT
75 X 8 mm MS -HV System, buried rail ,equipment and structure earthing in TSS
8 SWG GI wire - ACDB and DCDB, battery chargers, terminal board
6 SWG GI wire - Fencing panel and Local supply neutral
38) Check Painting
The exposed surfaces of earthing connections (MS flats) above ground level shall be
given two coats of painting to colour grass green
The bond connections on OHE shall be painted with two coats of black bituminous
paint
39) Check Maximum Value
Combined Earth value in OHM shall not be greater than TSS - 0.5, SSP/SP - 2, AT - 10,
Independent earth station- 10
40) Check Marking
Earth pit Shall be provided Box & Cover and the CE/IE Values to be stencilled with date
test & Earth pit No
41) Safety and Permission
A) Before starting the rail drilling work the following should be available
1. OHE bonding plan
2. Portable Rail drilling machine
3. Chamfering tool
4. Template for hole marking
5. Competent operator for drilling and chamfering
6. Helpers and whistle men
7. Necessary PPE , safety gadget, Flags and banners
8. Person with communication equipment at work spot and at both station on
either direction
B) The safety counselling to be done for the staff engaged to understand and follow
( Toolbox talk) the Safety rules and procedures like GR ,Joint Procedure order,
Circulars, Standing Instructions for safe working on track with block / caution
order including movement of trains
C) The EA engineer should be available at site and ensure necessary permits are
obtained and information is given to SMRs,SMs ( on either direction) and section
SSE/SE/JE Pway,S&T
D) The site should be cleaned before leaving
End of check sheet