Switching the switches
QIs it possible to use 240v house type light switches for my boat’s 12V LED spotlights? SPLITTY, via the CB website
ATONY REPLIES… Yes it’s perfectly possible and we have done it for 17 years, but it is not best practice.
Household switches are rated for AC: alternating current, which turns itself off for a split second 100 times a second as it alternates. So the instant you turn the switch off, the electricity supplying the switch turns itself off, preventing sparking as the contacts open. With battery-supplied DC (direct current) there is no such turn-off, so the design needs to prevent sparking and contact damage. Some mains switches may, in fact, be rated for DC, but I suspect most are not. Also the electronics inside those bulbs might cause a voltage surge as you turn them off, making any sparking worse (but I feel this is unlikely).
The mains switches have ample insulation for 12v, and with LEDs, the current is likely to be small; so subject to the above, such switches can be used at your own risk. It would be good practice to use ‘bootlace ferrules’ on the bare cable strands where they screw into the switches.