Isolation for 3 phase domestic installations

[Ian1981]

The Supplier will probably supply a 4 pole isolation after their metering anyway for the contractor to connect the tails to.
Perhaps not to be used by the user of the installation but it will be there all the same perhaps?
I do agree that it’s not a requirement in TPN installations which are not TT
Regulations 537.1.2 and 537.2.1.1 are the ones to note.

 

[johnduffell]

I always assumed the single phase two pole main isolation stipulation is in case the polarity is incorrect at the meter tails. This can go unnoticed indefinitely, whereas you'd do well to leave 3p with a neutral/live reverse and not get called back soon. Although if there is no three phase equipment it's possible, but unlikely due to the lack of 3p domestic installs.

The risk with 3p is the same one you'd have regardless with the integrity of the equipotential zone.