Current Rating for Copper Busbar

The following table shows current rating for different size of busbar. This information is very crucial especially in designing the busbar size for Electrical Switchboard.

(A) Main Horizontal & Vertical Copper Busbar Size

Item	Busbar Size	Rating (Ampere)
1	1 x 3 mm x 25 mm	100
2	1 x 5 mm x 25 mm	160
3	1 x 6 mm x 25 mm	200
4	1 x 6 mm x 30 mm	250
5	1 x 6 mm x 40 mm	300
6	1 x 10 mm x 30 mm	400
7	1 x 10 mm x 40 mm	500 - 600
8	1 x 10 mm x 50 mm	700
9	1 x 10 mm x 55 mm	800

 

(B) Main Horizontal Earth Busbar Size

Item	Busbar Size	Rating (Ampere)
1	1 x 3 mm x 25 mm	Below 800

 

(C) MCCB Line & Load Cable Size (BS 6004: 1984,450/750 V)

Item	Busbar Size	Rating (Ampere)
1	1 x 2.5 mm	6 – 16
2	1 x 4.0 mm	20
3	1 x 6.0 mm	30 – 32
4	1 x 10 mm	40
5	1 x 16 mm	50 – 63
6	1 x 25 mm	70 – 90
7	1 x 35 mm	100
8	1 x 50 mm	125 – 150
9	1 x 70 mm	175 – 200
10	1 x 95 mm	225 - 250

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