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Hi all,

I've been asked to carry our EICR reports on a large stately home. The house has around 20 C/U with around 15 circuits in each. All the wiring is VRI cable contained in metal conduit with no separate earths (conduit is being used as the earth). None of the C/U have RCD's fitted just MCB's. The main part of the house is private accommodation but parts are rented accommodation. The VRI cables seem to be in reasonably good condition.

So, my question is what observation codes should I use for non RCD protected circuits? and should I use coding to high light the VRI cabling?

Thanks in advance.
 
VR cable would suggest originally wired in the 40s ? i Would be surprised if no alterations were made since then
 
I would be having a good look round as there are probably loads of joints where additions alterations have been made and the VIR is compromised so go in with open eyes and Definatly carry out full testing of cables
if the wiring is good order and the op is satisfactory of the test results ,i would put down on the test sheet , under the circumstances that a rewire is in order has soon has possible .
 
Even testing the cable can cause problems as it is so ancient.
When I come across a circuit wired in VIR, I inform the customer that it should be rewired without delay.
In many cases an IR test will give good results, but as we all know, this cable will crumble in your hands, and is well past it's serviceable life.
I will not even attempt to offer any other course of action. If they don't want to take my advice that's their prerogative.
 
Much of the above is true but one cannot make a blanket statement that all VIR is automatically defective and too crumbly to touch. Some is totally shot, but equally I have VIR that is strong and supple and could be pulled into a conduit without damage just like the day it was made, even where it has been exposed. That does not mean it will last very long, but where replacement is not a trivial task, it might last long enough to tackle the rewire at a steady pace instead of an all-out panic.

Regarding the earthing, if the conduit is threaded that is still a perfectly acceptable form of CPC provided it is intact , properly terminated at the fittings and not modified with a hacksaw in too many places or corroded at the joints. However, installations old enough to be wired in VIR might contain slip-jointed conduit, which is not normally considered adequate as a CPC. So an evaluation of the type of conduit-work is needed to gauge the suitability as a CPC.
 
If the conduit has been installed 'loop in' style it may be easy to replace the cables with new PVC singles. Do check the cables though, I thought 'oh no' a while back on a steel conduit installation, only to find all the cables were actually PVC. The Zs readings were incredibly low.
 

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Thanks for all your comments so far. I'm very aware that disturbing the wire could cause issues with the insulation crumbling. Also, I agree the likely hood of the conduit being intact with have been altered over the years is slim. I have inspected a a couple of points and the VRI cables seem to been in very good order considering. The cables are flexible and no brittle or crumbling insulation, I've only done a very small inspection so far so things may change. I have seen that a previous electrician has altered some of the wiring and connected into the VRI cabling and renewed a circuit with new PVC 6491X cables, is this expectable? There's also the question if AFDD's should be fitted?
 
Check anywhere that the VIR may have been subjected to heat, such as batten holders and any other flush lighting fittings. I've also seen VIR that has deteriorated as a result of heat in ceiling roses, if the flex drop is short and a high wattage lamp fitted.
The insulation can drop off this stuff completely, but unless it's disturbed, the bare conductors will till have an air gap between them, so nothing will show on an IR test.
Fully agree that it's time this stuff was gone, but it helps persuade the customer if there's evidence to back this up.
 
There's also the question if AFDD's should be fitted?
While I think AFDD are a bit over-sold, this might be a place where it makes sense.

A stately home is going to be at risk of fire damage and often has largely irreplaceable contents and fittings. While cable in conduit is very good from a fire prevention point of view, it is not practical to check nothing has been butchered over the years with a poor DIY-style of fix, or bits of unenclosed VIR wire that might have been roasted by a high wattage bulb or electric heater.

Going all RCBO would be a very good start, as RCD/RCBO will trip of medium-resistance faults to earth (failed insulation, small rodent-triggered arc) that might start a fire, but AFDD do go that little further in also dealing with L-N faults and series arcs (perhaps, not definite, but better than other choices of OCPD).

Given the lack of RCD protection, changing the boards without doing a total rewire (assuming the VIR is OK at those ends as you seem to have found) in one go might be a better and more affordable plan for the owner to reduce risk. Also the SPD that would be part of such a change might also slightly reduce the risk of voltage-spike triggered faults.

In my opinion they should be planning to rewire in the not too distant future in any case, mostly due to the risk of seriously degraded VIR in unobservable locations.
 
Ive Got a bit of a cop out.

If I come across vir in a property I am doing an EICR on I stop and say to client sorry I don’t work on properties with vir and explain the issue with vir And recommend Removal and r3placement of vir cable.
I do not charge for any work carried out up to that point.

i do say other electricians will be willing to do the EICR, but I don’t.
 

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