Hmm the trench may need to be a bit wider than you thought, or indeed the example width of  450mm -  you did not say the magic word 'trench' to begin with....


OK, look here   either derate the single core rating of your AWA or whatever by the amount in 4C6 relative to the one wire case, not the already de-rated trefoil case.


Or look at the wide spaced trefoil on tray case,  (more on that here) and realise that with enough room for air flow  it can becomes more or less the same.

another old thread on non-trefoil groups.


In the limit you could have multiple separated trenches, but do not, as it will make length matching a sod.

There are tricks involving backfill with specially graded sands and things to improve the dissipation, but see how close you are without that.


M.

Hmm the trench may need to be a bit wider than you thought, or indeed the example width of  450mm -  you did not say the magic word 'trench' to begin with....


OK, look here   either derate the single core rating of your AWA or whatever by the amount in 4C6 relative to the one wire case, not the already de-rated trefoil case.


Or look at the wide spaced trefoil on tray case,  (more on that here) and realise that with enough room for air flow  it can becomes more or less the same.

another old thread on non-trefoil groups.


In the limit you could have multiple separated trenches, but do not, as it will make length matching a sod.

There are tricks involving backfill with specially graded sands and things to improve the dissipation, but see how close you are without that.


M.