Ask an Electrician anything...

[Gary C]

We have a CU for the room with the main breaker and four B32 breakers and no real option to install much else other than protected 13A sockets and the cost would be prohibitive to replace them all.

A type 3 unit in the CU seems to be the best we could install. At least it would help with switching transients from the loom downstairs.

a SY2-D with its own B32 would at least be simple to install.

[Gary C]

dhutch said:

Or failing due to age? But understand giving them the best protection you can is key too.

What sort of machine are they, you say chips so obviously some electronics? Motor? Power draw?

Vintage 8 bit computers. So things like Commodore PET's, TRS80's, BBC Micro's, Apple ][.

I'm sure much of the failures are age related but every little helps.

[ruggedscotty]

Gary C said:

ruggedscotty said:

Gary C said:

RS, here's one for you

I work for a museum thats suffering from some vintage equipment failure.

As its in a large victorian mill, with many uses and a carpet manfacturing shop, I wonder if I am getting mains borne surge/spikes that could be damaging things.

I can't get my hands on a fluke 1773 or similar and wondered if there are any consumer unit mounted mains filters that we could use ?

I suppose what we really need is an isolating 1:1 transformer but thats probably going too far

Wondered if anyone has come across similar ?

Oh the fluke analyser would be the way to do it...

What sort of power is being taked about here, what are you trying to support, and dioes it have high start up currents etc... If it is mains borne then the consumer unit surge protection could have a part to play. However.... What if the surges are originating from the equipment in the museum. That would be interesting.

Could the equipment be operated from DC ? I know thats a bit of a biggie as it would take some doing to change out your switches to dc from ac. but it has had benefits in the past at reducing harmonics and surges in some places.

back to distribution units and surge protection. This protects the installation from external surges going to the installation. However you could fit these at various places in and around to try and iron out the surges if originating within the installation.

https://www.tlc-direct.co.uk/Products/CGSRG1VCU.ht...

https://www.amazon.co.uk/dp/B0B945MDQ8/ref=sspa_dk...

https://www.electricaldirect.co.uk/browse/consumer...

https://cauk.tv/articles/power-quality-issues-tran...

We have four 32A ring mains and run quite a few (read far too many) machines off one ring and given their vintage nature (40 years old some of them) earth leakage can be a little suspect.

However there real issue is machines failing and I'm wondering if mains borne spikes are pushing some vintage chips over the edge.

Thanks for the info

A SY2-D sounds Ideal. Wiring, it looks as if you install it on a DIN rail through its own B32 CB and it then protects all circuits on that CU ?

https://www.surgedevices.co.uk/wp-content/uploads/...

Edited by Gary C on Monday 20th March 20:00

https://www.surgedevices.co.uk/wp-content/uploads/2022/04/Surge-Installation-Guide.pdf

Yup surge device on the bus, protecting the connected loads.

[Gary C]

ruggedscotty said:

https://www.surgedevices.co.uk/wp-content/uploads/...

Yup surge device on the bus, protecting the connected loads.

Cheers.

[ruggedscotty]

Ohhhhh

TRS-80

I MAY HAVE TO VISIT..... lol

[Gary C]

ruggedscotty said:

Ohhhhh

TRS-80

I MAY HAVE TO VISIT..... lol

Please do

https://www.tripadvisor.co.uk/Attraction_Review-g4...

But don't look at the wiring !

[dhutch]

Gary C said:

Please do

https://www.tripadvisor.co.uk/Attraction_Review-g4...

But don't look at the wiring !

Nice.

[ruggedscotty]

Gary C said:

Please do

https://www.tripadvisor.co.uk/Attraction_Review-g4...

But don't look at the wiring !

That looks cools that does. Thinking about what your after.... Maybe a dual conversion UPS ? then galvanic isolation ? that would pull the issue as far away as you could electrically...

Also are you networking them ? could the network cables be an issue ?

Edited by ruggedscotty on Tuesday 21st March 09:42

[_-XXXX-_]

Gary C said:

Vintage 8 bit computers. So things like Commodore PET's, TRS80's, BBC Micro's, Apple ][.

I'm sure much of the failures are age related but every little helps.

With old computers it tends to be old electrolytic caps failing. The BBC Micro is famous for it (kits on eBay). What sort of failures are you experiencing?

[RichB]

dhutch said:

Gary C said:

Please do

https://www.tripadvisor.co.uk/Attraction_Review-g4...

But don't look at the wiring !

Nice.

Those rows of screens look like many of the offices I worked in.

[silentbrown]

Not planning to do this myself, but just curious how you'd locate a break in the live on a socket ring.

Our EICR flagged this up, and I suspect it's just a loose live on a socket, and I've checked a few by eye without seeing any issues.

Would you disconnect one leg of the ring in the CU, then see which sockets don't work?

[Gary C]

_-XXXX-_ said:

Gary C said:

Vintage 8 bit computers. So things like Commodore PET's, TRS80's, BBC Micro's, Apple ][.

I'm sure much of the failures are age related but every little helps.

With old computers it tends to be old electrolytic caps failing. The BBC Micro is famous for it (kits on eBay). What sort of failures are you experiencing?

The BBC common failure isn't the electrolytics, its the paper X2 RIFA's (Just overhauled 15 BBC micro PSU's for the classroom display)

Its not the caps that concern me, its the vintage silicon. A lot is just the age but just repaired a 3032 PET that needed two new counters, a BCD to decimal decoder, a SRAM and a VIA replacing. Machine has run for a week and now I have a report that its gone down again (and yes, its capacitors are ok, especially the big +5V one)

So it got me thinking about wondering about the supply.

The Mill is about 200 years old but I have no idea what type of earthing arrangement it has. I imagine we are fed from a Phase & Neutral off an incomming TP&N supply with Neutral & PE connected but the site might even have an earth of its own So I have no idea about the mains borne transients we might suffer without suitable monitoring. I know the artificial turf manufacturing has some bigish machinery because you can hear it start up, but what else is in the building, god only knows.

I would really like to replace all the 13A sockets with protected ones, but that is far too expensive (its a small museum with limited funds) so Consumer unit based protection would appear to be perfect.

Ultimately I would like a Inverter based digital UPS system to produce a pure sinewave regardless of the input, but thats probably out of our range

[Teddy Lop]

silentbrown said:

Not planning to do this myself, but just curious how you'd locate a break in the live on a socket ring.

Our EICR flagged this up, and I suspect it's just a loose live on a socket, and I've checked a few by eye without seeing any issues.

Would you disconnect one leg of the ring in the CU, then see which sockets don't work?

If visually checking make sure it isn't a case of some monkey screwing the terminal screw into the insulation or sleeving rather than copper, not uncommon.

Simplest way is probably to disconnect all ring conductors at the CU, then connect L-E together on one ring leg only, then low resistance test at each socket, expect some to be open. Then do the same for the other leg. The fault should be at or lie between the two that gave you the highest readings for each leg, although spurs and corroded/cheap sockets can introduce resistance and throw you off if testing from the plug side rather than terminals behind.

[Gary C]

ruggedscotty said:

That looks cools that does. Thinking about what your after.... Maybe a dual conversion UPS ? then galvanic isolation ? that would pull the issue as far away as you could electrically...

Also are you networking them ? could the network cables be an issue ?

Edited by ruggedscotty on Tuesday 21st March 09:42

Lol, most don't even know what a network is ! let alone have them.

[ruggedscotty]

silentbrown said:

Not planning to do this myself, but just curious how you'd locate a break in the live on a socket ring.

Our EICR flagged this up, and I suspect it's just a loose live on a socket, and I've checked a few by eye without seeing any issues.

Would you disconnect one leg of the ring in the CU, then see which sockets don't work?

very adpt name... silent brown lol

This is the issue with a ring, 32A breaker and 2.5mm cable... you could have the full 32A flowing through that one section of cable.

Anyways locating a break in the ring has to be done with the power off...

here is a video - https://www.youtube.com/watch?v=BKd7_dHBnG8

what your trying to do it locate where it is.

Ive done it with a multi meter before - Power off, pulled the cables out the breaker and then Put one cable to neutral and then went round the ring with a plug modified so that I could check for continuity. White board marker. Mark each socket that you got a reading at.

Go back take out the live from the first test and put the 2nd live to neutral and no the same again at each socket. You will locate the point at where the live is broken between two sockets.

it can take a lot of time and could result in you horsing through the walls to trace the cable.

[silentbrown]

silentbrown said:

Our EICR has flagged the lack of RCD on a socket ring circuit with a C2 "Unsatisfactory".

The EICR notes "older installations designed prior to BS7671:2008 may not have been provided with RCDs..." - As our installation is ~30 years old, does this imply it shouldn't have got a C2?

Thanks everyone for advice on this. Only eight days later and we've now got a shiny new CU installed and tested to latest regs - I've waited much longer than that for quotes on some jobs. Cost was less than I was expecting, which was a bonus.

[dhutch]

Good news.

It's pretty routine now.

[ruggedscotty]

Gary C said:

_-XXXX-_ said:

Gary C said:

Vintage 8 bit computers. So things like Commodore PET's, TRS80's, BBC Micro's, Apple ][.

I'm sure much of the failures are age related but every little helps.

With old computers it tends to be old electrolytic caps failing. The BBC Micro is famous for it (kits on eBay). What sort of failures are you experiencing?

The BBC common failure isn't the electrolytics, its the paper X2 RIFA's (Just overhauled 15 BBC micro PSU's for the classroom display)

Its not the caps that concern me, its the vintage silicon. A lot is just the age but just repaired a 3032 PET that needed two new counters, a BCD to decimal decoder, a SRAM and a VIA replacing. Machine has run for a week and now I have a report that its gone down again (and yes, its capacitors are ok, especially the big +5V one)

So it got me thinking about wondering about the supply.

The Mill is about 200 years old but I have no idea what type of earthing arrangement it has. I imagine we are fed from a Phase & Neutral off an incomming TP&N supply with Neutral & PE connected but the site might even have an earth of its own So I have no idea about the mains borne transients we might suffer without suitable monitoring. I know the artificial turf manufacturing has some bigish machinery because you can hear it start up, but what else is in the building, god only knows.

I would really like to replace all the 13A sockets with protected ones, but that is far too expensive (its a small museum with limited funds) so Consumer unit based protection would appear to be perfect.

Ultimately I would like a Inverter based digital UPS system to produce a pure sinewave regardless of the input, but thats probably out of our range

Had a think about this.... If its just PC's then surely a cheap double conversion would suffice, and does it need to be a UPS ?

https://www.criticalpowersupplies.co.uk/p/tripp-li...

How about.... the wild card...

12 or 24 v power supply - to a battery. then an invertor to 220v. this invertor supplying a dedicated circuit and distribution out to the computer systems. And only the computers. Monitors and others can be driven from normal mains but your computers from the dedicated supply.

The invertor feeding a db with your RCD and breakers for the computers and a clean earth provided to the DB for your PC earth and this being kept seperate from the mains earth. Invertor output still needs to be earth rodded and RCD protected. And the neutral on the invertor grounded.

[SEDon]

dhutch said:

LED? With integral driver? Glass case or aluminium. I would say the bulb is fairly and putting a voltage to earth.

All Led with integrated drivers, don't think it's the bulb(s) unless they're all faulty as i've tried just having one bulb on and it still trips. Takes about 20 minutes to go off when only one bulb connected, instantly when 3-4 connected

[dhutch]

ruggedscotty said:

Had a think about this.... If its just PC's then surely a cheap double conversion would suffice, and does it need to be a UPS ?

https://www.criticalpowersupplies.co.uk/p/tripp-li...

How about.... the wild card...

12 or 24 v power supply - to a battery. then an invertor to 220v. this invertor supplying a dedicated circuit and distribution out to the computer systems.

Isn't that pretty much what's inside a double conversation UPS unit?