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Old 9th August 2020, 02:35 PM
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There's a lot of exposed metal on an F30. Safety was not always uppermost on designer's minds back in the day, so I agree an earth is well worth adding.

Saying that, an RCD should prevent electrocution in the unlikely event of the metal becoming live, but you get no warning as it will not trip until you touch the live metal - had it been earthed, it would trip immediately the short occurred and will refuse to be reconnected until the fault is cleared. A fairly recently (re)wired house will have at least one RCD in the consumer unit.

Colour enlargers with a transformer may not need one as the voltage is stepped down to 12 or 24 volts via an isolating transformer and that is not enough to push a dangerous amount of current through the human body. Even then, a fault in the transformer can put 240V on the output instead of 12/24V (a typical failure mode for cheap USB chargers - NEVER buy cheap USB chargers!) so it's still worth having as a belt-and-braces addition but by no means essential. A colour enlarger with separate low-voltage power supply is a "Class III" device and is considered safer in this regard than "double insulated" (Class II). The double-insulated device should have either the class designation or the double-insulated symbol (one rectangle inside another) on the label.

Last edited by Bob; 9th August 2020 at 03:18 PM.
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