I've just installed a new (1 way, ceiling pull cord) switch in my bathroom since the old one broke. When I came to change it, it was not wired the way I expected with the live into the COM terminal and the 'neutral' into the L1 terminal (it had a black wire into the COM and red into L1 (old UK wiring colours)). I decided to copy this wiring on the new switch despite the standard being red to COM and black to L1.

My main question is, does it even matter if it's wrong (and has been wrong on the old switch for years)? Intuitively on a single switch it doesn't seem like it should matter.

  • The installation instructions only mention "N"(eutral), "Loop", and "Line". What do you mean by COM and L1? Mar 25, 2019 at 17:37
  • That link doesn't seem to show the actual switch. I couldn't find the product page on the MK website but the actual product was this one screwfix.com/p/mk-6a-1-way-pull-cord-switch-white/… Mar 25, 2019 at 17:57
  • Normally L1 would be the line and com would be your neutral, or that's the method on this side of the pond.
    – Ed Beal
    Mar 25, 2019 at 18:56

1 Answer 1


Dumb switches care not

A simple, dumb SPST light switch cares not which end is "line" and which end is "load". In fact, in North America, the two live terminals on a basic light switch are not distinguishable from each other! The labeling on your switch is probably a matter of convention, to keep with how more complex switches (such as multi-way switches) and lighting controls are labeled.

  • @OllyRundell -- we say "thanks" here by upvoting and/or accepting folks' answers :) Mar 26, 2019 at 23:45
  • OK - thanks for letting me know! I don't have the 'reputation' to upvote publically but have accepted and upvoted! Mar 28, 2019 at 14:00

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