Quick Q

[Craig W]

Sorry fellas, just wondering if you have 16mm mains coming from the street into a 100A fuse and then into the top of your main switch, what size cable should be going from the bottom of the main switch to the first breaker and linking to the next breaker etc? Just asking because i think mine is 2.5mm2, doesn't have bars.

[patty]

It Usually comes from the Fuse/s to the meter/s then out of the load side of the meter/s to the main Switch out of the bottom of the main switch to feed your circuit breakers and or to a Designated Supply sealed Active link the cables coming from your the bottom of the main sw vary to what circuit breaker/load they are supplying

[Craig W]

From the bottom of the main switch it looks like a 2.5mm going from the bottom to a 20a CB then another 2.5mm2 going to the next 20a CB, again to the next 20A, then to 10A and 10A, all i wanted to know is if 2.5mm was big enough, i mean i would have thought they'd use 6mm from the bottom of the main sw to the first breaker and maybe then 2.5mm onwards.

[patty]

What you are describing is correct!! 2.5mm is rated @ 20A

[mxchris69]

if they were using 2.5mm they should of taken each one back to main switch. at the moment they have a 2.5mm which if the 3 breakers are at maximum load will have 40 amps

[thatirwinfella]

mxchris69 is correct with this.

remember, the 2.5mm is used to describe the cross sectional area of the cable, not the diameter, circumference or radius. you can't really determine a cable size by measuring across it, so if you've tried something like this to size your cable you may actually have the wrong size.

as to the original question, how long is a piece of string. it depends on how it's wired, what the load for that circuit is, etc.