Button on a railing

[mattylad]

You may be better having a lower voltage I.E. 12v going to the switch and it then powering a 12v relay that switches the mains, that way there are no potential issues that may cause a danger.

And in that case, forget the switch and use a sensor that needs no moving parts, no holes through the box - you just wave a hand (or your keys) at it. (still switching a relay).

 

[trojanhawrs]

It’s a plain old black iron railing, like every other plain old black iron railing.

Some have a kind of box section post that you could use to contain the cable/switch terminals.

 

[sparkymarka]

Or kinetic

 

[Alec_t]

Needs to be mains voltage.

Very risky on an external steel railing, where it could be subject to vandalism and idiots electrocuting themselves. Safer to use low voltage switching of a relay.

 

[pete01]

Very risky on an external steel railing, where it could be subject to vandalism and idiots electrocuting themselves. Safer to use low voltage switching of a relay.

It will hopefully be on an rcd....

 

[mattylad]

Even an RCD is IMO too risky when in a public place.
Extra Low voltage is the way to go.

 

[pete01]

Even an RCD is IMO too risky when in a public place.
Extra Low voltage is the way to go.

Outside lights (bollards) all over the shop in public places.

But yes extra low better if possible.

 

[endecotp]

Regarding voltages, it's actually 5V DC but not isolated (not SELV) so I believe best treated as if live for e.g. the spec of the button.

I believe best practice would be for it to be double-insulated and to not connect the railings to the earth in my cable, hence the plastic box in my photo. If I used a metal box fixed to the railings, and connected it to the earth conductor in my cable, that would be an extraneous conductive part, right?

 

[endecotp]

you could also use some metal steel conduit brackets/U clamps.

Thanks, that's a pretty good idea. The railings are about 24mm diameter so a 25mm conduit saddle would work well - metal or plastic, to suit the chosen box.