Will this old consumer unit pose any issues with an upcoming EICR?

[Neptune]

I've had invaluable advice from this forum in relation to EICR's and clarifying my understanding that just because the consumer unit is "old", it does not need to be replaced. Since then, I had the EICR carried out at my rental property. This went to plan.

I am now scheduling my next EICR on a separate property and this has an even older Consumer Unit but everything works and seems safe e.g. no cracked fittings or exposed cables from my pre-inspection checks.

My question: will this type of Consumer Unit be okay to produce a satisfactory EICR?

Thanks in advance.

 

[nicebutdim]

The inconvenience of RCDs is much overstated IMHO.

This is undoubtedly true but, from a customer's perspective, one circuit out is always going to be much less inconvenient than six - even if it only happens once in 10 years.

I've dealt with a total of two RCD tripping incidents at home. One was caused by an oven element failing and caused almost no inconvenience. The other incident involved repeated trips, which caused the loss of all hot water and I couldn't get a competent electrician to investigate, before finally fixing the problem myself.

Incidentally, it was the latter issue that spurred me (no pun intended) towards the idea of trying to retrain in the industry.

 

[Deleted account]

Perhaps "huge" was an exaggeration but I have been quoted £500 for the Dual RCD board. Includes materials and fitting. £620 for RCBO's.

I’m very surprised at the difference there.
ID say no more than £50 difference between the two choices, maybe at a push £60.

However I’d be charging £650 for an RCBO board change with surge protection as standard, so the price is good.

I don’t do split RCD boards because in my opinion there is such a small difference in price between them you may as well get the better board.

 

[Dartlec]

This all RCBO versus split load RCD keeps coming up on here. I wired my place just under forty years ago with a three RCD board and all 12 circuits through one or other of them. All RCDs are in full working order, but, apart from when I've been playing and managed to short a neutral and earth together, the only times I've ever had one trip is when an immersion heater element failed and the dishwasher sprung a water leak.
The inconvenience of RCDs is much overstated IMHO.

I'm always impressed when I see places with an up front board how rarely they actually trip when I ask.

Until you are replacing a socket and accidentally let the neutral graze the earth of course...?

 

[Dartlec]

Where is the mains cable isolated from? When I look at the board in my own house, there is no other isolation point that I can see before the board. Unless it's lurking in the metre box outside the house...

Some older meters in some areas contained isolators apparently (never seen one myself), but naturally the modern smart meters have not been designed with such useful features....?

Ideally any new installation would have an isolator, but in practise they are often not put in because the cost the DNO charge for them is ridiculous.

The 'correct' answer is that one books an appointment with the DNO to come out and remove the fuse while the electrician carries out work, then arrange for them to return at the end of the work to replace it.

You can imagine how well this works in practise, or indeed how often it ever happens....

 

[Neptune]

I don’t do split RCD boards because in my opinion there is such a small difference in price between them you may as well get the better board.

What’s a better board? And what are the limitations of a dual RCD board?

 

[Mike Johnson]

An all RCBO board, With an RCD board all the circuits it protects go off when it trips.

 

[pc1966]

What’s a better board? And what are the limitations of a dual RCD board?

The RCBO board is better in the sense that an earth leak fault on one circuit only trips that circuit, and not a group of circuits off one of the 2 RCD in a dual RCD board.

Historically the first system to protect against a fault making conductive stuff (metal boxes, etc) "live" and so presenting an electric shock risk from touching it was to have an earth connection to any metal work, and so in the event of a fault a lot of current flows, the fuse would blow, and power was disconnected. This was known as EEBADS from "Earthed Equipotential Bonding and Automatic Disconnection of Supply" and today is still the starting point under the more generic term of ADS (the Automatic Disconnection of Supply aspect).

To make ADS work you need a low impedance earth so enough current flows to make the supply disconnect on the fuse or breaker that is normally providing fault/overload protection. Where such an earth was provided by the power supply company it would originally been in the form of the 3rd conductor (after L & N) back to the supply transformer (the TN-S supply).

But if you were in the middle of nowhere then often the supply company would not provide that as it makes the supply 50% more expensive which adds up on km of a route. In this case you would end up with a 'TT' supply where your earth was a rod (or similar) buried in the ground by your property. The problem with earth rods is it is very difficult to get a low resistance in to soil, and it can vary due to frost or drought, so in most cases not enough current would flow to blow even a small fuse and so ADS fails to protect.

So for old TT installations they have the VOELCB (voltage operated earth leakage circuit breaker) which was quite a simple device that sensed the voltage between the property's "earth" and the rod and tripped if anything significant happened. While better than not disconnecting they were not very reliable in practice as various different faults could escape detection.

The replacement was the RCCB (residual current circuit breaker) also known by the more generic term RCD (residual current device). This senses the difference between current going out and returning (the "residual") and if it sees enough going astray disconnects. While they don't have to be electronic, in practice they all are, and when they first came out were very expensive and so only one was fitted in the TT supply case to make ADS work at all.

But folk kept dying of electric shock, especially from garden power tools, so folk started fitting a sensitive RCD to outdoor sockets or extension leads. These were sensitive enough to disconnect on the small leakage current that a human could (usually) survive and so protecting against touching L (from a cut cable, etc) while standing in the garden, etc.

Eventually it became a requirement for sockets in general which in a property might be on several circuits. However, if you have one RCD feeding them then a fault on any of the circuits disconnects power to all of them. Also this makes fault finding difficult as it is not always the obvious circuit that is actually at fault, it might just be provoking a trip on a neighbouring one due to a N-E fault.

As prices dropped you started seeing dual RCD boards, advertised as "high integrity" since you had less trouble in the event of a fault, typically half you house's lights & sockets would still be working.

But these days with the ever falling cost of electronics and options to miniaturise them, you now can have the RCBO which combines the RCD and the overload MCB in one device. This is ideal as then a fault is only impacting on the faulty circuit, any not the other healthy ones.

 

[Deleted account]

What’s a better board? And what are the limitations of a dual RCD board?

You do not get any better fault protection from an RCBO board. Circuits will still trip within the stated times under specific fault conditions whether it’s RCD or RCBO.

it’s the inconvenience of loosing half the circuits in the house if you have one faulty appliance or socket on on any one circuit. With RCBOs you only loose the circuit that has the fault.

as @pc1966 says the cost of RCBOs has fallen dramatically in recent years to the point that the boards are so close in price. In some cases they are the same price. If you only had four circuits the RCD and RCBO boards could be identical in price.

@Neptune Why are you up at 4.16am

 

[Mike Johnson]

I never thought of myself as a man of few words, but it seems I am.

 

[Soi disant]

as @pc1966 says the cost of RCBOs has fallen dramatically in recent years to the point that the boards are so close in price. In some cases they are the same price. If you only had four circuits the RCD and RCBO boards could be identical in price.

A trend which is now reversing, and probably will until demand increases.

Type A RCBOs aren't too bad, but have you seen the price of Type F and Type B?

 

[nicebutdim]

A trend which is now reversing, and probably will until demand increases.

Type A RCBOs aren't too bad, but have you seen the price of Type F and Type B?

It's not a case of this trend reversing, but of the same trend being repeated as different technology is required and becomes more widely available.

Compare relative prices of different protective devices over the years and you should find that pricing has consistently followed a downward trend. This does tend to reverse with older tech as demand drops and supplies dry up.

Not that many years ago, I would guess that RCBOs were prohibitively expensive, but for Type AC the price is generally very low. With demand for Type A devices having increased, we've seen prices drop to quite reasonable levels and will see further drops as Type AC devices becomes less popular. If use of Type B or F remains uncommon, prices will remain comparitively high, but that will change if/as demand increases.

 

[Mike Johnson]

A trend which is now reversing, and probably will until demand increases.

Type A RCBOs aren't too bad, but have you seen the price of Type F and Type B?

In answer too: as @pc1966 says the cost of RCBOs has fallen dramatically.

Seems to say that the cost of RCBO's in increasing, seems contradictory and wrong as the demand for RCBO's is higher than it's ever been.

 

[Soi disant]

What it costs to install RCBOs is increasing as the requirement for devices beyond Type AC increases.

Type A RCBOs aren't too bad, particularly in budget makes.

Type F and Type B are expensive, and we're back to the situation where an RCCB and some MCBs is significantly cheaper than RCBOs.

 

[pc1966]

I suspect the type B/F will remain expensive for some time as they need something fancier than a toroid transformer to do the diff current measurement at DC (e.g. Hall effect or fluxgate sensor). Unless they get to real mass-market numbers there is little incentive to make them any cheaper/simpler as it is hard to get the return on design & development costs.

Personally I would slap a tax on any mains powered appliance than needs anything more than type A RCD, otherwise they will just push that cost on to the electrical industry and then to the customer by the back door instead of including their own protection.

 

[nicebutdim]

What it costs to install RCBOs is increasing as the requirement for devices beyond Type AC increases.

Type A RCBOs aren't too bad, particularly in budget makes.

Type F and Type B are expensive, and we're back to the situation where an RCCB and some MCBs is significantly cheaper than RCBOs.

The increased costs you refer to are because of requirements to fit less commonly used types of RCBO, but those are also slowly dropping in price as they are manufactured in greater numbers.

All new technology is expensive as manufacturers need to recoup costs associated with design, development, tooling etc. As demand increases, so does competition and prices drop.

This also assumes that people need to have these types of protective devices on their installation. While many people will undoubtedly embrace technology that demands this sort of protection, surely many more people are like Mavis at No. 23 and gain more than adequate protection from Type A devices?