Lights Out!

Feb 20, 2026 Last reply: 4 months ago 6 Replies

Gentlemen,



I was in my workshop earlier today buggering around, when - with no provocation at all - the lights all went out. My lights are in 3 clusters, each with their own switch. I checked the breakers and sure enough, the breaker for the lighting (which supplies these 3 clusters) had thrown-out. So I thought I'd turn 'em all off, then switch them back in one at a time to find out which cluster was causing the problem. The first time I tried this, cluster 1 came on fine. Then I turned on cluster 2 and that was fine, too. On switching in cluster 3, however, the breaker tripped again immediately. So I thought I'd narrowed the fault down to cluster 3's circuit. Anyway, to cut a long story short, when I repeated this test, with all



3 clusters switched off, it was impossible to reset the lighting breaker; it just popped out immediately, even with none of the lights switched on. I'm just wondering if the fault therefore might be in the breaker itself. Can they just 'go' like that with no warning? And if so, what's the typical failure mode?

Cheers,



CD


  1. Let the breaker cool down
  2. You may have a short

For clarification, the "breaker" in question, are we talking about a MCB, RCD or RCBO?

What kind of lights are they (i.e. LED, Flu tube etc)?

They're all LED types so low current. These are just regular over-current breakers, not GFI or anything like that.

Ah. so no 'cold filament' inrush

Something is seriously weird.

Mice ate your cables?

It's not guaranteed to be pre switchgear. A short on cluster 3 could have welded the lightswitch contacts closed. You need to disconnect the load side from the lightswitch

Well breaker failure is not unknown. Nor are rats

If you have the gear, disconnecting the mains from the circuit and using a megger or even ohmeter might bring something up

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required