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

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!

littlespark · Mar 14, 2023

Haha. Well this is awkward…

I’ve just reported #29 as a possible bot / hacked account as I couldn’t see how the content referred to the thread…. But as there has been messages since by the same author, I may have jumped the gun somewhat.

Apologies.

pc1966 · Mar 14, 2023

littlespark said:
Haha. Well this is awkward…

I’ve just reported #29 as a possible bot / hacked account as I couldn’t see how the content referred to the thread…. But as there has been messages since by the same author, I may have jumped the gun somewhat.

Apologies.

Well at this point in time #29 is by @marconi and he is definitely human!

DPG · Mar 14, 2023

pc1966 said:
Well at this point in time #29 is by @marconi and he is definitely human!

Yeah that's worked out a bit unfortunate now that the post had been removed and the numbering changed

littlespark · Mar 18, 2023

DPG said:
Yeah that's worked out a bit unfortunate now that the post had been removed and the numbering changed

Still there for me ??

Second cottage to do next week, finish the workshop…. Then start on big hoose!

Better get my running shoes looked out and make sure my Fitbit is charged up.
I’m expecting 20k steps a day!

Rockingit · Mar 18, 2023

It's cases like this where it's the duty of the Inspector to remember the first principles of the task - is it fit for continuing safe use?

Yes, we use markers and references to various regulations to help us make that decision and that now outdated concept of 'did it meet the regs in place at the time' is thankfully no longer an opt-out, but ultimately it's the experience and judgment of the inspector that's on the line. For example - you IR a circuit buried in an old hollow wall and get a reading of 2.1MOhm, technically that's compliant so not notable, yet to any of us with experience it instantly rings alarm bells and is probably either very old cable at the point of severe deterioration or vermin damage. So now you have to consider continued safe use, not just what's on your meter. And that decision probably isn't just electrical, it's informed by all the other adjacent information around us - is that cable buried in a stone wall or does it likely run up through that roof void full of tinder dry old crispy mice nests...... etc.

It's a responsible thing to do, which is why all these fly by inspection companies boil my pee so much.

littlespark · Mar 18, 2023

not come across any spurious readings so far, but I bet the 80/90’s t&e will break down before any bulletproof MICC….
A bad pot would have failed well before now.

The cost of replacing fuse boards when some are built into bigger panels is going to be cost prohibitive, but there are some rcd sockets been fitted in rooms that were used for catering.

Other boards have been changed in the past where the old fuse board has been used as a joint box and a newer CU fitted.

Can’t wait to open than literal can of worms.

pc1966 · Mar 18, 2023

Unless you had a duff brand/batch of T&E its usual downfall are mice, UV exposure, or mechanical abuse (trapped, nail, etc).

I too would be very weary of IR readings below 10M unless I could identify why!

littlespark · Mar 18, 2023

pc1966 said:
Unless you had a duff brand/batch of T&E its usual downfall are mice, UV exposure, or mechanical abuse (trapped, nail, etc).

I too would be very weary of IR readings below 10M unless I could identify why!

There could be mice… possibly.

It’s a shame when an otherwise great installation with neatly clipped MICC, surface conduit etc gets ruined by a bit of sticky backed mini trunking down the side of a lovely period architrave.

littlespark · Mar 21, 2023

Getting well into the workshop today… just the general power and I’ve got issues.

So it’s the white CU I’m testing in the middle.
Top left MEM SW/fuse feeds the cafe, top right feeds the public toilets and in turn, the two holiday cottages.
Bottom left is main sw/fuse “M” turns off everything. And bottom right is busbar chamber that everything feeds off.

Haven’t checked fuse sizes in “M” yet. Cannot isolate white CU without turning off cafe and cottages. Whatever size is in “M” is the OCPD for this white CU. I’ll find out when I can turn off the cottages… there’s guests in just now.

But… from the CU. There’s an rfc with 3 doubles. From this, an unfused spur goes into the shop next door… for another 8 points!
I’ll either suggest fusing down here, or pulling out the spur, extending the cable back to CU and making the shop its own radial circuit.

Workshop and shop also share the lighting circuit. Could do with separating that as well.

Only 4 circuits out of a 5+5 dual rcd board used, so plenty spares.

The 2 RCDs are tripping out at 46 and 62 ms. At x1 I

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

Rockingit · Mar 21, 2023

I'm assuming (hoping!) that the 3ph red conductors out of the MEM are suitably 'slotted'?!

littlespark · Mar 21, 2023

Rockingit said:
I'm assuming (hoping!) that the 3ph red conductors out of the MEM are suitably 'slotted'?!

Yes…. Wooden “washer” between trunking and mainswitch. Oval hole. Not individual holes.

No eddies going on here.

marconi · Mar 21, 2023

Rockingit said:
I'm assuming (hoping!) that the 3ph red conductors out of the MEM are suitably 'slotted'?!

Some readers might welcome a little explanation on this learning point.

littlespark · Mar 21, 2023

marconi said:
Some readers might welcome a little explanation on this learning point.

You mean…what’s the difference between Eddie currents and Eddie The Head?

nicebutdim · Mar 21, 2023

Eddie Currents and Eddy the Head...

nicebutdim · Mar 21, 2023

Posted in anticipation

littlespark · Mar 21, 2023

nicebutdim said:
Posted in anticipation

it wasn't the start of a joke.

littlespark · Mar 22, 2023

Eddy current: a localized electric current induced in a conductor by a varying magnetic field.

Eddie the Head: or just “Eddie”. Long serving mascot of band Iron Maiden. First appearing in 1980.

Eddy currants can be produced by passing live conductors through separate holes in a metal sheet. (Ferro magnetic) such as entering an enclosure.

This effect is negated if the conductors all pass through one bigger hole.

DPG · Mar 22, 2023

littlespark said:
Eddy current: a localized electric current induced in a conductor by a varying magnetic field.

Eddie the Head: or just “Eddie”. Long serving mascot of band Iron Maiden. First appearing in 1980.

Eddy currants can be produced by passing live conductors through separate holes in a metal sheet. (Ferro magnetic) such as entering an enclosure.

View attachment 106965

This effect is negated if the conductors all pass through one bigger hole.

And eddy currants?

littlespark · Mar 22, 2023

DPG said:
And eddy currants?

You’re raisin the bar there with your jokes.

DPG · Mar 22, 2023

littlespark said:
You’re raisin the bar there with your jokes.

I thought I'd be the first one to point out the auto-correct on your otherwise excellent post!

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