Quick check on cable size

[JohnW2]

My issue with using a contactor with a remote switch without also using a standard DP isolator is what happens if the contactor gets jammed on.

Is a contactor more (or much more) likely to get 'jammed on' than is a 'standard DP isolator'?

Even Main Switches in CUs have been known to get 'jammed on' (it happened to a friend of mine not long ago). This is why we test for dead', no matter what we think we have 'switched off' (and maybe also 'locked off').

Kind Regards, John

 

[flameport]

Many contactors are only suitable for functional switching, and are not suitable for isolation or emergency switching.

Others can be used for all three things.

 

[JohnW2]

Many contactors are only suitable for functional switching, and are not suitable for isolation or emergency switching. .... Others can be used for all three things.

As a matter of interest, what features/characteristics of the 'many' and the 'others' result in this difference?

According to Table 537.4 of BS7671, contactors to BS EN 60947-4-1 are suitable for 'all three things', whereas those to BS EN 61095 are suitable only for functional switching.

Edit: in terms of what TLC are offering, it appears that the MK ones are part of the 'many', but the Wylex ones part of the 'others'.

Kind Regards, John