This is going to take me weeks.....

marconi · Mar 7, 2023

littlespark said:
Started with one of the holiday cottages today… and a handful of C3’s already. Nothing too serious.

Non standard set up. 2 cottages adjacent to each. Supplies come from one of the big DBs from the main house. Big DB also feeds public toilets.

From photo you can see SWA coming from main DB into isolator+mcb on right, through meter, for simple monitoring, then into cottage DB

You can get a bus through the holes the tails go through.

Underfloor heating in both cottages is fed from boiler for toilets… so that sw/fuse is live when cottage is isolated, and also on a different phase.

I believe (and will check next week when I do other cottage) that the hard wired smoke detectors are supplied from this cottage, but also feed the ones next door. Which means next door has all 3 phases present.

View attachment 106624

Some less experienced folk will learn much from how you approached this job. You're a top man.

littlespark · Mar 9, 2023

Started on the cafe this morning… mapping circuits rather than testing… but this is the start of the interesting stuff.

Original 3ph fuse board with HRC cartridge fuses. Later added modern CU with RCD mainswitch, monitoring meter again.

Mix of metal conduit, plastic conduit, surface T&E and MICC…. Sometimes within the same circuit!

Joints in the trunking… including a 100A Henley block to supply the newer CU.

Oversized fuses for size of cable…. All lights on one fuse….

And I’m puzzled about the cable supplying the 3ph cooker. (3 separate fuses, I believe only single phase loads within the cooker itself, however)
The cable isn’t SWA. It’s 5 core (numbered on black) with a braided outer and transparent plastic sheath. I should have taken a better photo.
Come across it before on agricultural for grain dryer motor controls etc.

Isolated upstream in workshop, 63A MEM switch fuse complete with asbestos flash pads.

[ElectriciansForums.net] This is going to take me weeks.....

MJPD29 · Mar 9, 2023

littlespark said:
Started on the cafe this morning… mapping circuits rather than testing… but this is the start of the interesting stuff.

Original 3ph fuse board with HRC cartridge fuses. Later added modern CU with RCD mainswitch, monitoring meter again.

Mix of metal conduit, plastic conduit, surface T&E and MICC…. Sometimes within the same circuit!

Joints in the trunking… including a 100A Henley block to supply the newer CU.

Oversized fuses for size of cable…. All lights on one fuse….

And I’m puzzled about the cable supplying the 3ph cooker. (3 separate fuses, I believe only single phase loads within the cooker itself, however)
The cable isn’t SWA. It’s 5 core (numbered on black) with a braided outer and transparent plastic sheath. I should have taken a better photo.
Come across it before on agricultural for grain dryer motor controls etc.

Isolated upstream in workshop, 63A MEM switch fuse complete with asbestos flash pads.

View attachment 106695

Is cooker cable SY possibly?

littlespark · Mar 9, 2023

MJPD29 said:
Is cooker cable SY possibly?

It’s possible. I should have taken a better photo.

They have the same stuff running between halfway along the basement of main house and an outside boiler room… but in 7 core 1.5mm
2 runs of at least 50m between boiler controls in both locations.

littlespark · Mar 13, 2023

Better photos of the mystery cable. 5 cores. (That I can see) and the braided cable.

Fairly recent addition as cores use brown/grey/blue tape as identification whereas some older cables using red/yellow/blue/black

littlespark · Mar 13, 2023

To those following this thread....

I'm having a mare already. Slight disagreement between myself and the old boy caretaker about what i'm coding the EICR. (he used to be a spark back in the 80's i think, and has done some of the maintenance before he got too old)

Ill not divulge straight away, but simply ask you guys to convince me im not going soft.

Taking the cafe as an example. What would you code, remembering all the large metallic appliances. Kitchen staff, but members of the general public in the seating area in the vicinity of sockets and heaters.

Old circuits are still on BS88 fuses.
Every light on the same fuse.
The 3 phase oven on 3 separate fuses. (although only single phase loads. Loss of one phase isn't going to cause massive problems)

The other distribution boards are much the same.... old bs88's in some places... fuse wire in others.
Some "upgraded" to circuit breakers, but there are very few RCD's across the whole site.... even in the modernised areas.

I don't want to come across as touting for work, but at what point do you have to say, look, this is unacceptable these days.... especially with public being able to access parts of it.

westward10 · Mar 13, 2023

You really ought to know that is SY cable.
The fact the public have access to xyz isn't really relevant.
Separate fuses for a three phase oven is fine in fact it would be fine for the majority of circuits.

plugsandsparks · Mar 13, 2023

Well FWIW, if its all the correct vintage (which it probably is), not much you can do but code it strictly to BS7671. I have come across similar installs and wrote a separate report on my recommendations, because the Amtech S/W i use is messy when it comes to making a case for upgrade. Last job i recommended RCBOs to all sockets based on, blah, blah and i was pleasantly surprised when they agreed.

Flanders · Mar 13, 2023

Nothing wrong with bs 88 fuses as long as they are rated correctly for the cable size. Code 3 for the sockets if they are not RCD protected . Could push to a code 2 if you believe they are being used outdoors. . Why do you think the metal appliance are an issue.

westward10 · Mar 13, 2023

littlespark said:
Started with one of the holiday cottages today… and a handful of C3’s already. Nothing too serious.

Non standard set up. 2 cottages adjacent to each. Supplies come from one of the big DBs from the main house. Big DB also feeds public toilets.

From photo you can see SWA coming from main DB into isolator+mcb on right, through meter, for simple monitoring, then into cottage DB

You can get a bus through the holes the tails go through.

Underfloor heating in both cottages is fed from boiler for toilets… so that sw/fuse is live when cottage is isolated, and also on a different phase.

I believe (and will check next week when I do other cottage) that the hard wired smoke detectors are supplied from this cottage, but also feed the ones next door. Which means next door has all 3 phases present.

View attachment 106624

It doesn't matter that there are separate phases it is not a departure.

pc1966 · Mar 13, 2023

Separate fuses per phase are only a real issue if it can lead to a 3P motor limping along on a single phase and overheating, possibly becoming a fire risk. Normally the motor overload protection should stop that anyway and it is not a likely problem for such a property.

As above, I would follow the BPG#3 guidance which, though less readable now, is still C3 for no RCD in low-risk areas (i.e. typically indoors) and C2 for high risk areas (like out doors or in bathroom areas, etc.)

Lights all one one fuse is a bit dumb, but if loss of light is a serious risk anywhere then having emergency lighting is far more important as it also deals with a power cut.

I don't like SY cable but it is OK for indoor use (not UV tolerant) where the braid is not actually needed for penetration protection (not rated to clear OCPD). Its not really a very useful situation, but not specifically bad if those are not needed. SWA or Flexishield/BS8436 are cables that meet the penetration aspect, though for the foil types it is often only to a modest OCPD let-through like 20A MCB or similar.

westward10 · Mar 13, 2023

Lighting circuits across three phases which share a common neutral, quite common in large scale warehouses and factories require linked circuit protection so separate fuses would not be suitable.

pc1966 · Mar 13, 2023

westward10 said:
Lighting circuits across three phases which share a common neutral, quite common in large scale warehouses and factories require linked circuit protection so separate fuses would not be suitable.

Of course, otherwise a borrowed neutral on a grand scale!

marconi · Mar 14, 2023

littlespark - After just over a week you have 808 views. Well done Sir. Folk are reading your posts with interest.

Do you keep a before and after record - written or photo - of the corrections you do for free or billed?

Do you do IR surveillance? ie:

Infrared Electrical Inspection, Electrical Testing Finds Hot Connections - Albany, NY | Infrared Imaging Services - https://www.infraredimagingservices.com/electrical-infrared/

If not then perhaps an added value yet paid for extra to such work as you are doing now? I have found it very useful in an industrial setting.

pc1966 · Mar 14, 2023

marconi said:
Do you do IR surveillance? ie:

Infrared Electrical Inspection, Electrical Testing Finds Hot Connections - Albany, NY | Infrared Imaging Services - https://www.infraredimagingservices.com/electrical-infrared/

For a couple of years I have really wanted an IR camera for this sort of thing, but in my case more for curiosity so I can't justify the £1.5k or so they cost!

This is going to take me weeks.....

marconi

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littlespark

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MJPD29

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littlespark

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littlespark

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littlespark

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westward10

plugsandsparks

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Flanders

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westward10

pc1966

westward10

pc1966

marconi

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pc1966

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