I didn't think old pearl lamps caused fuse wire to blow. I have never known it.
It's only an issue for B6 MCB's
It's only an issue for B6 MCB's
I'm plenty old enough, but soon decided that the sensible course was to keep a spare, already wired, 5A fuse on top of the CU!
Kind Regards, John
You haven't lived
[the difference between clear and pearl was obviously irrelevant]. Particularly when lighting circuits were heavily loaded with incandescent bulbs/lamps, it was pretty common for one of them dying to take out a B6 MCB - at least, IME.Kind Regards, John
Nope. Non maintained emergency fitting! Kinda redundant with RCBOs though, they basically never go
You haven't lived
Kind Regards, John
Agreed with mcb's , but as andy says, I have never known them too take fuses out.
Oh, I misread what Andy wrote
. Yes, I agree with you both that dying lamps 'never' (at least, IME) blew a fuse. That makes sense, and I wouldn't expect a dying lamp to ever trip the thermal part of an MCB (which is roughly equivalent to a fuse), either, since the very high current that can flow during the death throes of an incandescent bulb/lamp is of such very short duration. However, those large currents clearly do often flow for long enough to trip the magnetic part of an MCB.Kind Regards, John
Even though they had 2 screws, the screws were quite small compared with the big one screw on the newer boards.
Im sure, early versions had two neutral screws as well.
The heads on the neutral ones often snapped off IME.
I do recall a few times the back bit of the fuse base burning out a few times, but you could unscrew it and replace it easy
Im sure, early versions had two neutral screws as well.
The heads on the neutral ones often snapped off IME.
I do recall a few times the back bit of the fuse base burning out a few times, but you could unscrew it and replace it easy
That's true, but the screws appeared to be quite adequate (no smaller than those used in many of the accessories connected to the final circuits concerned) and the redundancy of having two clearly reduced the chances of problems due to 'loose connections'.
IIRC, all the one's I've dealt with had dual neutral screws (in a really solid 'neutral block').
I don't recall having personally experienced that - at least, to any significant extent.
Overall, I would personally say that they were 'beautiful' bits of engineering, particularly in comparison with what followed!
Kind Regards, John
Is it me or should that be "increased"
Edit
Redundancy
2. Something redundant or excessive; a superfluity.
My apoligies
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Unusual perhaps, but I've had it happen once or twice.
I think it's essentially 'you'Is it me or should that be "increased"
What I meant was that having dual screws "reduced the chances of problems of 'loose connections' ".That is not quite the sense in which the word "redundancy" is used in engineering and related contexts. Yes, "excessive and superfluous" under normal (fault-free) service conditions but providing valuable "belt and braces" protection in the presence of faults. I doubt that you would regard it as "superfluous" to have 'redundancy" of flight control systems and instrumentation in an aircraft you were about to board
Kind Regards, John
It's obviously not impossible, but I cannot recall having ever personally experienced it.
Kind Regards, John
Low quality lamps perhaps, which didn't have inbuilt fuses
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I have the gubbins of an old 60A 604 right in front of me and it has 6 neutral ways.
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