ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 2 of 11
SIZING OF CABLE TRAY 1.
SCOPE This calculation covers the Sizing of Cable Tray with respect to Cable Data consideration required for all equipment of “New Propane gas compressor” project at LPG-1 plant, Uran complex of Oil & Natural Gas Corporation limited (ONGCL). The panels for all the equipment are considered to be located in existing LPG-1 substation. Power supply will be from new PMCC to be located in the LPG-1 substation.
2.
3.
BASIS & ASSUMPTIONS 2.1
Electrical Design Basis for New Propane Compressor (Doc. No. section C2.8 of 6867-00-50-50DB-01 rev. B, clause no.7.2 & 14.2 “Cable laying philosophy”).
2.2
Cable Data as per Cable Schedule doc. no. 6972-010-50-50-CSH-0021.
2.3
Cables are considered to be laid in single layer.
2.4
Spare capacity of 10 % is considered for cable trays (as per ‘Design Philosophy for Electrical Facilities’ clause no. 7.2.5 of cabling system).
2.5
Refer ‘Design Philosophy for Electrical Facilities’ Cl.no: 7.2.8 of cabling system – for cable tray design related to loading.
2.6
Cable data for sizing of cable trays have been selected based on the Standard chart of “Polycab” make Copper & aluminium conductor, XLPE insulated, armoured cable conforming to IS 7098 part-1/1988.
CABLE TRAY /LADDER SPECIFICATION 3.1
Refer Standard Specification no. 6-51-0082 rev. 2, Clause no.3.1 & 4.1 of “Cable Trays & Laying”.
3.2
Cable ladders are recommended for sizes above 300mm.
3.3
Cable trays shall comply with the requirements specified in EIL installation standard (7-51-0333).
3.4
HT Power, LT Power and control cables shall be laid in separate trays wherever trays are used.
3.5
Refer to NEC table 318-9 for the maximum fill area for multicore cables.
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 3 of 11
SIZING OF CABLE TRAY TRAY SIZING CALCULATION:
4.
4.1
CABLES FROM LPG-1 S/S TO NEW PROPANE GAS COMPRESSOR 4.1.1 Cable tray from LPG-I to New Propane gas compressor shed (New Propane gas Compressor) LT Cable size
No.
Overall Dia. (mm)
Total length of Tray required (mm)
3c x 4 mm²
7
15.0
7 x 15 = 105.0
4c x 6 mm²
5
18.0
5 x 18 = 90.0
3c x 70 mm²
1
30.0
1 x 30 = 30.0
3c x 95mm²
3
33.0
3 x 33 = 99
3c x 185 mm²
2
45.0
2 x 45 = 90
3.5c x 35 mm²
1
26.0
1 x 26 = 26
3.5c x 50 mm²
1
29.0
1 x 29 = 28 Total: 468 mm
(Copper conductor up-to 16 mm2). Sum of total Diameter for LT Power cables = 468 mm. With spare capacity of 10%, size required = 516 mm Recommended tray size for single layer of LT cables: Select from the Standard Cable tray sizes available = 1no. X 600 mm. Cables are touching to each other.
For cable tray drawing refer annexure II (b)
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 4 of 11
SIZING OF CABLE TRAY 4.1.2
Cable tray from LPG-I to New Propane gas compressor shed (New Propane gas Compressor)
LT Cable size
No.
Overall Dia. (mm)
12P x 1.5mm2
2
29.7
2 x 29.7 = 59.4
2
8
21.6
8 x 21.6 = 172.8
2
10C x 2.5mm
3
21
3 x 21 = 63
6C x 2.5mm2
4
15
4 x 15 =60
2
3C x 2.5mm
4
14
4 x 14 = 56
3C x 4 mm2
1
15
1 x 15 = 15
2
12
2 x 12 =24
6P x 1.5 mm
2
2C x 2.5mm
Total length of Tray required (mm)
Total: 436.2 mm (Copper conductor up to 16 mm2). Sum of total Diameter for LT Power cables = 436.2 mm. With spare capacity of 10%, size required = 480 mm Recommended tray size for single layer of LT cables: Select from the Standard Cable tray sizes available = 2no. X 300 mm. Cables are touching to each other.
For cable tray drawing refer annexure II (c)
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 5 of 11
SIZING OF CABLE TRAY 4.1.3
Cable tray from Panel no. 19 in LPG-I to New Propane compressor 6.6kV HT motor
HT Cable size 3c x300mm²
No.
Overall Dia. (mm)
Total Diameter (mm)
1
80.0
1 x 80 = 80.0 Total: 80 mm
Sum of total Diameter for HT Power cables = 80 mm. With spare capacity of 10%, size required = 88 mm Select from the Standard Cable tray sizes available = 1no. X 300 mm.
For cable tray drawing refer annexure II (a)
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 6 of 11
SIZING OF CABLE TRAY 4.2
CABLE TRAY FROM LPG-1 S/S TO LPG-2 S/S 4.2.1
Single core cable
LT Cable size 1C X 300 mm2
No.
Overall Dia. (mm)
12
41
Total length of Tray required (mm) 12 x 41 =492 Total: 492 mm
Sum of total Diameter for HT Power cables = 492 mm. With spare capacity of 10%, size required = 542 mm Select from the Standard Cable tray sizes available = 1no. X 600 mm. Spacing between cables is 80 mm after trefoil connection
For cable tray drawing refer annexure I (a)
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 7 of 11
SIZING OF CABLE TRAY 4.2.2
Control cable (run through 4’’ GI conduit)
LT Cable size 10C X 2.5 mm2
No.
Overall Dia. (mm)
2
21
Total length of Tray required (mm) 2 x 21= 42 Total: 42 mm
LT Cable size 3C X 300 mm2
No.
Overall Dia. (mm)
2
80
Total length of Tray required (mm) 2 x 80= 160 Total: 160 mm
Sum of total diameter for control cables = 42 mm. Sum of total diameter for HT Cables =160 mm. Total diameter of control and power cables is 202 mm (42 + 160). With spare capacity of 10%, size required = 223 mm. Select from the Standard Cable tray sizes available = 1no. X 300 mm
For cable tray drawing refer annexure I (b)
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 8 of 11
SIZING OF CABLE TRAY 5. TRAY SIZING VERIFICATION:
5.1
CABLES FROM LPG-1 S/S TO NEW PROPANE GAS COMPRESSOR
5.1.1 Cable tray from New PMCC to Field Equipment (New Propane gas Compressor)
5.1.1.1 LT Cables laid on 600mm tray are as follows: Run
Core
7 5 1 3 2 1 1
3 4 3 3 3 3.5 3.5
Size - mm2
Overall Diameter (mm)
4 6 70 95 185 35 50
Weight of Cable kg/km 545 X 2.45 740 X 1.45 1350 X 0.35 1655 X 1.05 2835 X 0.7 910 X 0.35 1125 X 0.35
15 16.5 30 33 45 25 28 TOTAL
7316
5.1.1.2 LT Cables laid on 2 NOS. 300 mm tray are as follows Size - mm2
Run
Core
Overall Diameter (mm)
2
12P
1.5
29.7
8
6P
1.5
21.6
740 X 0.78
3
10
2.5
21
665 X 1.05
4 4
6
2.5
15
620 X 1.13
3
2.5
14
435 X 1.07
1
3
4
15
545 X 0.35
2
2
2.5
12
385 X 1.25
TOTAL OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
Weight of Cable kg/km 945 X 0.7
3775
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 9 of 11
SIZING OF CABLE TRAY
5.1.2 Cable tray from Panel no. 19 to New Propane compressor 6.6kV HT motor
HT Cables laid on 1no. 300 mm tray are as follows:
5.2
Run
Core
Size - mm2
Overall Diameter (mm)
Weight of Cable kg/km
1
3
300
80 TOTAL
7140 X 0.35 2499
CABLE TRAY FROM LPG-1 S/S TO LPG-2 S/S
5.2.1 HT Cables laid on 600 mm tray are as follows:
Run
Core
Size - mm2
Overall Diameter (mm)
Weight of Cable kg/km
12
1
300
41
1840 X 3
TOTAL
5520
5.2.2 Control Cables along with HT Cables laid on 300 mm tray are as follows: Run
Core
Size - mm2
2
3
300
80
2
10
2.5
21
665 X 0.5
TOTAL
3903
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
Overall Diameter (mm)
Weight of Cable kg/km 7140 X 0.5
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
DOCUMENT NO: 6972-010-50-50-CAL-0020
Page 10 of 11
SIZING OF CABLE TRAY Conclusion:
Thus the Cable tray size selection meets all the requirements of:a) Spare Capacity (10%) b) Allowable fill area (as per NEC table) c) Cable load (as per Design Philosophy for Electrical Facilities – Cl. no: 7.2.8
OWNER
ONGC LIMITED B 25/11/2011 REV. NO. DATE
PMC
LSTK
ENGINEERS INDIA LIMITED Approval PA PURPOSE PREPARED
SAVAIR ENERGY LIMITED PP MD REVIEWED BY APPROVED BY
