Electric Ring Final Circuit downrating concern

Section62

anselld said:

The the numbers look fine for a normal installation.  It is difficult to see what they are worried about.  Perhaps they are concerned about the total load exceeding 100A if you fully loaded every circuit simultaneously, but that is the case for many/most installations.  They need to apply a thing called "diversity" to the loads.

I wonder what the supply to the property is rated as.  It could be as low as something like 40A.  Councils did sometimes skimp on electrical supplies to their properties, or rather they were supplied according to the needs of the day, not what we'd expect in the modern era. (e.g. shared services were commonly used).

Swapping the 32A MCBs for 20A isn't necessarily the right solution if something like that were the problem, but maybe that is what the council are thinking?

Another possibility is they have seen the 2.5mm figure and taken that as the total conductor CSA rather than it being a ring with 2x 2.5mm.

Norman_Castle

OP, Have you had an EICR electrical safety check, if so, when? The landlord is required by law to do this check.

Section62

Val45 said:

I dread the thought of the possibility of frequent tripping if the supply is dropped to 20A.

Try not to worry too much.

20A is still a significant current, and depending on the type of MCB used the actual current required to flow for a given length of time before the trip goes can be significantly greater than that.

If the high capacity water distiller draws a high current for an extended period of time, the electrician should have taken that into account in their "diversity" assessment, and possibly provided a dedicated circuit for it rather than it being plugged into a ring with other appliances.  If they weren't concerned about that then I think it is probably unlikely you'll have significant issues with unwanted tripping, unless you have several other significant loads on the same circuit (e.g. kettle, toaster, coffee machine) and use them at the same time.

If there were a problem, it would be the council's responsibility to do something about it.  They shouldn't leave you in a position where there are MCBs regularly tripping.

anselld

Norman_Castle said:

OP, Have you had an EICR electrical safety check, if so, when? The landlord is required by law to do this check.

The OP has stated they had a new installation by a qualified electrician (with Landlord permission) which was fully tested and a copy of the certificate forwarded to the Landlord.  That certificate would be valid for five years before a further EICR would be required.  (although I think the Council also do them on change of tenant)

The issue is why is the Landlord questioning the validity of the installation and demanding modifications based purely on the paperwork and without any further viewing or testing.  That is the question the OP needs to put to the Landlord, otherwise we are just guessing.

Section62

Val45 said:

In part 2 of the DCN18C it reads; New consumer unit installed in new position to facilitate new kitchen layout. Kitchen ring main and Heating control positions altered and new cabinet underlighting installed.

Just another thought - when/how did the ex-coal store and garden shed get their supplies?  Was it part of this job, and if so, why no mention in the quoted text?

The supply to the garden shed is the one which would give me a bit of a wobble - a 10mm/40A shed supply is a lot for a one-bed council bungalow, most people would typically have something like one double socket and a light or two in their shed.

It could be this has been a trigger to the council wanting to get their electrician into your property to take a look at what is going on - with swapping the MCBs just being a pretext.

Val45

Hello. Thank you to all who have taken the time to respond to my post. 

To Norman_Castle. No, I have not had an EICR electrical safety check in all of the 12 years that I have lived here. 

To Section62. I am trying not to worry. Thank you for your kind reassurance. 

To anselid. The electrician that did my job told me that the Certificate would last five years. That is how I feel so confused and the reason why I came here. 

I have received a forwarded email from my daughter in law today which she has received from the Office. It contains two posts - one from the office to someone else, “Please find attached EICR and email from the tenants daughter in law for the following remedial.” And a reply back to the office, “We have a similar report carried out by one of our operatives in July 2020 – the socket circuits still need downrating due them being wired in 2.5mm cable through a loft containing insulation the repair wasn’t carried out there and then as we don’t stock. The repair still needs to be carried out the tenant isn’t getting charged for this either, the lad that attends will need 3 20A British General MCB’s” 

This reply back boggles my mind. 

My daughter in law forwarded the Domestic Electrical Installation Certificate to the Office by email, not an EICR. There has never been an Electrical Installation Condition Report done on this property during my tenancy. How is it possible that they can claim such? 

How can there be a similar report when no report has ever been made from this address? 

How can they know that the wires in my loft run in exactly the same way as some other persons, if they haven’t been seen? 

Why has the need for two 20A ‘things’ now become three? 

I am completely at a loss. Please can someone suggest what action I must take to rectify this situation?

Val45

I can think of no reason why the council are insisting on a downrate. When the electrical work was completed back in August 2019 I forwarded to them the Domestic Electrical Installation Certificate. I had expected a visit from them shortly after that to check things over but I heard nothing from them until February of this year. 

I received a letter dated 15th February 2022, headed “Maintenance and Remedial Works - Access Required Urgently” Further through the letter it states “These works have been identified from the last periodic inspection carried out which may have been undertaken by the council either recently or in some cases up to 24 months ago. ... As part of your tenancy agreement with the Council your home must be maintained to a decent and safe standard...” which left me dumbfounded. I have lived in this rented accommodation since 2009 and never in all of that time had they come to do an electricity check. 

When the two men came (28/02/2022) I asked them the reason for their visit. The older man showed me two switch things in his hands and told me that they had come to take two out and replace them with these. When I questioned them further they repeated the same. After showing them the Certificate which they were obviously not aware of, they left. 

I received another letter from the Council in May 2022 to let me know that, ”as part of our programme of cyclical electrical checks to all properties in the borough, we require an electrician from our contractor to attend your home and carry out the electrical safety check and possible remedial repairs arising from the check. Your home was previously part of a periodic electrical inspection programme which identified remedial actions.” 

I heard nothing more until I received a letter dated 13th July 2022 stating that I would receive a visit by an electrical inspector on 21st July and informing me that the inspection would take about 2 hours to complete, during which time the electric supply to my home would be turned off. Two men arrived late in the day, the youngest carrying some sort of switch in each hand and the other with a writing board tucked under his arm. They didn’t appear to have any tools with them. When I asked what they intended to do I was given the same explanation as the February visitors, “We have come to change the switches” I called their attention to the Electric Certificate laid on the table and asked where was the problem but neither could give me an answer as such, just that they had been instructed to take two switches out and replace them with these. In my frustration I decide to ask them for their permission to take their photo now and another while they were doing the job, adding that I would be holding them personally responsible if I had any electrical problems in the near future. The older chap then hurriedly rang his office and then moved outside to continue his conversation. After a while he returned to inform me that I would be hearing from the office shortly. He then beckoned to the other who had remained inside with me and then they left. 

I felt so uneasy after their visit that when my Daughter-in-Law arrived to take the dog out I asked her if she would get in touch with the office to find out what was going on, as I felt that I couldn’t cope with another visit like that.

 

 

anselld

I guess you can only write back to "the office" and ask them to show you a copy of the EICR which recommended the proposed work.

It may be that they know all the houses are of a similar construction and all have the same "issue".   Although if this is a genuine issue I would think it applies to a large proportion of the housing stock in UK where loft insulation has been added.

Section62

Val45 said:

“We have a similar report carried out by one of our operatives in July 2020 – the socket circuits still need downrating due them being wired in 2.5mm cable through a loft containing insulation the repair wasn’t carried out there and then as we don’t stock. The repair still needs to be carried out the tenant isn’t getting charged for this either, the lad that attends will need 3 20A British General MCB’s” 

Ok, this bit makes sense of what they are proposing to do.

The maximum current that should be allowed to flow in a cable is designed to keep the cable below a certain temperature to avoid problems such as damage to the insulation.

The maximum temperature a cable will reach depends on the current, the ambient temperature, and the amount of airflow/types of material around the cable that may carry heat away, or keep it in the cable.

For example, the maximum current that should be allowed in a  2.5mm cable which is clipped directly to a wall is 27A. "Clipped directly" is what is known as a 'reference method' - these are descriptions of typical installation methods.  "Cliped directly" is one of the best methods in terms of avoiding build-up of heat.

If a cable runs through an insulating material then less heat will be able to escape and the cable will get hotter.  This means that to keep the cable below the 'safe' temperature, the maximum current has to be lower (or use a larger cable).

If the cable is above a plasterboard ceiling and covered by insulation greater than 100mm thick then reference method 101 has to be used to work out the maximum current - which is 17A for a 2.5mm cable.  This is what they mean by "downrating" (derating).  There are other derating factors that need to be applied - for example if lots of cables are bunched up together.

So, the council think your circuits need downrating (i.e. protected by lower current trips (MCBs)) because they believe the wires in the loft are under insulation and can't operate safely at a higher current level.

Have you had any other work done on the bungalow recently, such as the loft insulation being increased?

Has anyone from the council looked in the loft to see where the cables are?

Did your electrician leave any paperwork referring to the cables being under (or over) the loft insulation?

Most of all, don't worry too much.  There's unlikely to be an immediate safety issue - the issue has more to do with long-term damage to cables being run at higher temperatures.

anselld

However, 2 x 17A ( for a ring) still has margin on a 32A breaker.
And how do the Council know the cables run in the loft if they have not inspected.  It is not normal for power cables to run in a loft, usually under or between floors.  Perhaps more likely in a bungalow.