C3

[ianfish]

New one to us. buying a 1930s semi which we believe was rewired late 80's 

 

All seems ok, but the conveyancer has forwarded an electrical survey which has c3 on a handful of points throughout the property. 

 

is this to be expected or something we need to look at in more detail?

 

domestic electrical installation condition report.

part 6

 

plastic consumer unit under stairs.

no circuit charts diagrams

no RCD protection on lighting circuits installed pre 2015

 

part 10 

 

4.4 consumer fire rating

4.11 charts omitted

5.11 c cables in walls

5.11 d

5.11 e

 

 

 

 

Edited October 15, 2019 by ianfish
pressed post too quickly add in c3

[Jeremy Harris]

Welcome.

 

TBH, it would be hard to do an EICR on any house that's more than a few years old and not have one or two C3s on it.  All it means is "Improvement is recommended" and can often be down to the judgement of the person doing the EICR.  Last one I did I noted a C3 for a cooker switch that was slightly too close to a hob, another C3 for a (metal) consumer unit that didn't have any RCD protection (wasn't required for the date of the installation) and another C3 because the meter tails were only 16mm², again fine for the date of the installation, but they need to be 25mm² to comply with current regs.

 

If you list the C3s here one of us can tell you whether there's anything you need to do about them.  The fact that they are C3, and not C2, or even C1, means they aren't very serious issues.  One problem is that the old C4 classification has now been removed, as that was very useful for older installations, as it just indicated that the item was compliant with the regulations in force at the date of installation.

[ProDave]

In the good old days, there used to be a C4 category, compliant with an earlier version of the regs.  When that was removed, a lot of those now end up as C3's.

 

Nothing to worry about, it's only C2's and especially C1's that need to bother you.

[ianfish]

Could anyone give me (us) and idea of the scale of C3 works needed in the now edited first message please

 

We are fast assembling a list of needs attention when two weeks ago before conveyancing and surveyors became involved, we are realistic in just wanting to be as aware as we can be in what we thought at first to be a reasonably maintained house.

 

Thanks in Advance

 

Ian

[Jeremy Harris]

On 15/10/2019 at 16:23, ianfish said:

New one to us. buying a 1930s semi which we believe was rewired late 80's 

 

All seems ok, but the conveyancer has forwarded an electrical survey which has c3 on a handful of points throughout the property. 

 

is this to be expected or something we need to look at in more detail?

 

domestic electrical installation condition report.

part 6

 

plastic consumer unit under stairs.

no circuit charts diagrams

no RCD protection on lighting circuits installed pre 2015

 

part 10 

 

4.4 consumer fire rating

4.11 charts omitted

5.11 c cables in walls

5.11 d

5.11 e

 

 

 

 

 

 

No immediate action needed for any of those items, IMHO.

 

If you're ever having any major electrical work done, then just add a consumer unit change to the work list, and that will cover everything except the "cables in walls" point.  Not sure what that is, could be just that it wasn't possible to inspect buried cables in walls (bit OTT, IMHO, but some do record such points).

 

When a new consumer unit is fitted it will be fire resistant and include RCD protection, plus there will be (or should be) details of the installation left with you.

 

A consumer unit change will be around £80 to £100 plus labour, should take less than a day to change, inspect and test.  Labour rates vary, around here it would be around £200/day.

[ProDave]

Looking at your revised list of C3's, I see the old chestnut of "plastic consumer unit" has cropped up.  At least this guy has given it a C3, some try it on as a C2 to try and get a consumer upgrade done.  The Wiring regs are not retrospective so there are few circumstances where you MUST upgrade it.  As already noted if you were wanting lots of alterations on one of the circuits not rcd protected, then a CU upgrade might be worthwhile, but even then it could probably just be dealt with by fitting an rcbo

 

Personally I would not do anything to address those C3's other than bear them in mind when planning future work.

 

[ianfish]

1 hour ago, ProDave said:

 

 

Personally I would not do anything to address those C3's other than bear them in mind when planning future work.

 

 

The electrics are currently under the stairs, which is an area we are going to look at during our kitchen build so would seem to be almost seem less!

 

[andyscotland]

11 hours ago, ProDave said:

Looking at your revised list of C3's, I see the old chestnut of "plastic consumer unit" has cropped up.  At least this guy has given it a C3, some try it on as a C2 to try and get a consumer upgrade done.  The Wiring regs are not retrospective so there are few circumstances where you MUST upgrade it.

 

Completely true from a regs point of view. And certainly some regs change somewhat "for the sake of it" and really not worth thinking about on an older installation.

 

However worth noting the regs on plastic consumer units changed because of their role in a number of domestic fires, ISTR including some with fatalities as the consumer unit was under the stairs and blocked exit from the building.

 

In those cases the root cause was loose connections but the plastic contributed to the rapid early development of the fire.

 

So it is worth at least understanding why the new regs are what they are, and making an informed decision of the risk/reward of leaving it as-is (which you're perfectly entitled to do). This will also depend on circumstances : e.g. if the only thing above it is an old dry timber staircase that's the only means of exit it's a higher risk, if the cupboard has a plasterboard ceiling and you have other ways out you may be less worried. Similarly if it's near anything that vibrates there's more chance of something coming loose over time, if not and the connections have been tight for decades they probably aren't going to magically undo themselves in a hurry.

 

If it was me and I knew I was planning work in the area in the short to medium term I would probably leave it till then.

 

But in the meantime I'd think about other potential control measures e.g. perhaps putting a smoke/heat alarm directly in the consumer unit cupboard for early warning and getting semi-regular inspections of the connections (perhaps every couple of years, between full EICRs) to check they're all in good condition with no sign of loosening or arcing.

 

That said loads of houses with plastic consumer units haven't burnt down, only a few have, so you may think it's not that big a deal. Just depends on your risk appetite / whether there are other things in your life more worth worrying about.

 

I wouldn't worry at all about RCDs on lighting circuits and missing drawings : just be aware of it if changing screw-in lamps / drilling walls / changing fittings and make sure things are off before you work on them (which they should be even if you had an RCD).

 

20 hours ago, JSHarris said:

A consumer unit change will be around £80 to £100 plus labour, should take less than a day to change, inspect and test.  Labour rates vary, around here it would be around £200/day.

 

Though the cost can bump up if during the CU change they find other things that need to be done (e.g. a cable with a lower-than-acceptable insulation reading that can't be connected to the new board till that's fixed). Advantage here is you have a generally-satisfactory EICR so that's less likely to happen, but still worth bearing in mind.

[Onoff]

12 minutes ago, andyscotland said:

In those cases the root cause was loose connections but the plastic contributed to the rapid early development of the fire.

 

 

There was also that stately home that burnt down that had the METAL distribution board in its cellar. Iirc vermin got it through an open knockout, made a nest and a loose connection set it ablaze. The metal board acted like a wall mounted fire and the metal conduits and trunking like chimneys. 

[ProDave]

My gripe with metal consumer units, is they tackled the "problem" from the wrong end.  They did NOTHING to improve reliability of consumer units or find out WHY they caught fire (e.g looking at terminations, quality of switchgear etc) instead they put them in a tin box to try and contain the fire WHEN it happens.

 

 

[Jeremy Harris]

37 minutes ago, ProDave said:

My gripe with metal consumer units, is they tackled the "problem" from the wrong end.  They did NOTHING to improve reliability of consumer units or find out WHY they caught fire (e.g looking at terminations, quality of switchgear etc) instead they put them in a tin box to try and contain the fire WHEN it happens.

 

 

 

 

Exactly my gripe too.  They could have sorted the problem by just improving terminations, as these have got steadily worse over the years.  The older brass terminations that had two screws were pretty much bomb proof, and had the big advantage that they held even very thick wires firmly in place.  Some of the clamp gate type terminations are hopeless, especially with heavy gauge wires.  Move the wire a bit when fitting other wires and there's a pretty good chance it will loosen up. 

[andyscotland]

2 hours ago, Onoff said:

There was also that stately home that burnt down that had the METAL distribution board in its cellar. Iirc vermin got it through an open knockout, made a nest and a loose connection set it ablaze. The metal board acted like a wall mounted fire and the metal conduits and trunking like chimneys. 

 

Very true, metal isn't a magic fix-all and definitely with conduit/trunking fire stopping and workmanship becomes much more important. ISTR there's a thing somewhere in the IET info at the time they made the change about the importance of ensuring all openings/knockouts are properly closed too.

 

1 hour ago, ProDave said:

My gripe with metal consumer units, is they tackled the "problem" from the wrong end.  They did NOTHING to improve reliability of consumer units or find out WHY they caught fire (e.g looking at terminations, quality of switchgear etc) instead they put them in a tin box to try and contain the fire WHEN it happens.

 

Valid point and definitely more they could have tackled. All the same even if the quality of the terminations was improved there'll always be a risk of someone not actually making the connection properly and a metal box (absent nesting vermin) has a lot less combustible material near the terminals so the chance of an arc developing into a full-blown fire, and doing so rapidly before occupants are aware of smoke, is undoubtedly a lot lower. Suspect that they thought that was enough of an idiot-proof easy win to bring the risk to acceptable levels.

 

26 minutes ago, JSHarris said:

Exactly my gripe too.  They could have sorted the problem by just improving terminations, as these have got steadily worse over the years.  The older brass terminations that had two screws were pretty much bomb proof, and had the big advantage that they held even very thick wires firmly in place.  Some of the clamp gate type terminations are hopeless, especially with heavy gauge wires.  Move the wire a bit when fitting other wires and there's a pretty good chance it will loosen up. 

 

No argument there - but in my time I've found plenty of the old brass screws that just haven't been done up properly, or terminated sloppily with loads of exposed core and floating unsheathed earths etc. There'll always be homeowners/cowboys making dodgy connections so as much as improving manufacture quality (and idiot-proof-ness) would be good, I don't think that would 100% sort the problem - improving containment/separation from combustible material is a good fallback IMO.