Figuring out old system

[Deleted member 281264]

with two 32 amp circuits and one 16 amp circuit? immersion

 

[Harry Bloomfield]

There could be many possibilities, pull each in turn, and see what still works, and what doesn't - is the usual way to determine..

 

[Deleted member 281264]

There could be many possibilities, pull each in turn, and see what still works, and what doesn't - is the usual way to determine..

edit

 

[Murdochcat]

sockets, cooker and immersion would be my guess

BUT only proper checking can confirm this

 

[ETAF]

picture of the fuse/consumer unit - would help

 

[Deleted member 281264]

I will get a photo up later, it's a combi so no immersion but I think they did originally have hot water tanks fitted

 

[Murdochcat]

I will get a photo up later, it's a combi so no immersion but I think they did originally have hot water tanks fitted

So the 16A is probably the redundant immersion as most 1980's properties would have had an immersion

Why are you asking this?

 

[securespark]

I suspect it will be either a cooker or shower, a ring final circuit and a lighting circuit with the wrong fuse in.

As said, safely pull each fuse in turn and go round, noting what is not working.

 

[ebee]

It used to be not uncommon to have an immersion heater fed directly from a ring final too.

And it was so during the days when a 3KW fan heater or two were kept handy in cold weather.

That 30A fusewire let everybody know they blew(not just everybody in your house but often everybody in your street) .

You did not need modern communications or monitoring equipment, 30A fusewire is all you need.

 

[ericmark]

The old Wylex fuses

can be replaced with MCB's

just one screw holds the base in place, the standard house wiring years ago (70's) was 4 fuses lights, immersion, ring final, cooker and would be white, blue, red, red if that helps.

Personally I replaced the fuse box with a new consumer unit with all RCBO's but there is nothing forcing one to upgrade.

 

[flameport]

The old Wylex fuses can be replaced with MCB's

They can, but doing so achieves nothing.

 

[ebee]

Yes the MCBs that replace fuses just Thwack, not anywhere as interesting as a great big Bang

 

[ericmark]

I will admit the tripping time needs considering, with a fuse the difference between the potential short circuit current of 160 to 130 amp would mean just a fraction of a second longer to disconnect with a short circuit, but with a MCB it would change from 0.01 seconds to maybe over 5 seconds I have not got the chart to hand, so the need to carefully measure the loop impedance became very important when moving from a fuse to an MCB.

However I did not think it was worth going into that, maybe I was wrong, clearly we should be looking as a new consumer unit with SPD and all RCBO's but some people simply can't afford the upgrade. Because I can does not mean others can.

 

[ebee]

Agreed Eric.
I think, in fairness, Flameports short answer about MCBs replacing fuses, was purely to make a point rather than going into all the whys and wherefores that I`m sure he could go into greater details about differing conditions but decided not to cloud the issue to the more "ordinary person" types.

Remember some years back there was a concern about the time some manufacturers were making 2.5 T & E with a 1.0 earthwire rather than the 1.5, somebody did the calcs and decided that , under some conditions, the 1.0 could vaporise before disconnection completes. I think it caused a "mini stir" at the time because some folk were wondering if they had left themselves open by error but in truth, not very often a problem but it could happen, not impossible.

There are times where a simple off the cuff answer gives a better reaction than all the caveats.

example, I never mentioned that putting in thicker fusewire in fuseholders or even doubling it etc gives far more interesting bangs if you survive to tell the tale.

 

[ericmark]

Fuses are a subject on their own, I know with some applications a semi-conductor fuse is better than a MCB.

However I am wary about telling anyone to draw a fuse. I know ionisation is rare, but flicking a RCBO or MCB off is very different to drawing a fuse.

The normal would be switch off between each test, and try with just one fuse at a time inserted, but it is time consuming turning the power off each time.

I wanted to see where my power was going, so easy to clamp the main tails and turn the RCBO's off one at a time, so I know 1.69 amp total drops to 1.11 amp if back of house turned off, and 1.21 front of house, does not make sense I know, clearly some thing turned on during test, and got 3.96 amp when re-energised. But my point is easy to flick a RCBO/MCB off/on to see what it controls, not quite so easy with fuses.

We do tend to have computer displays today, be it because solar installed, EV charging, or a smart meter, we no longer rely on the speed of the wheel on the electric meter.