electric on all the copper plumbing in the house

The fact you are experiencing them with the main switch off and they are "very mild" suggests it could simple be the result of a TN-C-S supply where your house taps are bonded to the supply "earth" but that is combined on the supply (DNO) side with the main neutral conductor for the network (the 'C' in TN-C-S). Then depending on the load imbalance on the various properties fed from that segment of cable you might see 5-10V difference between the tap (on supply earth) and the ground (true Earth).

Obviously it should be checked in case there is something more serious or strange taking place as from my armchair in Scotland I can't divine the true situation, but the checks you report suggest that might be the case.

If it is the above and essentially "safe" (see * below) but still bothers you there are possible solutions but they are not trivial. One option is if there is the option for installing a very low resistance earth rod / buried mat to try and pull the DNO earth down and the local Earth potential up to meet it, but that is very hard to achieve if not part of something big, like a lightning conductor network or building foundation rebar that is bonded.

Another solution is to change the house earthing arrangement from TN-C-S (where it uses the supplier's earth) to TT where you have your own earth rod. But to do so also requires some analysis and changes to your CU (consumer unit = fusebox) as then disconnecting on a fault will almost always need RCD protection, and ideally that would be two layers to avoid any single point of failure ( see ** below), so something like a 100mA delay-trip incomer RCD followed by the usual 30mA "instant" RCDs for additional shock protection.

[*] There are cases with the combined protective earth/neutral (PEN) of the DNO breaks, and this is potentially dangerous as the neutral current from everyone on the faulted segment of the supply tries to find its way home by other paths, which can be bonded service pipes, etc. Inside a home the open PEN fault case is not too dangerous (though it can damage equipment due to over as well as under voltage operation, and overheat inadequate bonding conductors) but it is considered a serious risk for some outdoor systems, such as EV chargers where you might be washing the car at the time so wet, conductive, and on the true Earth. In those cases you must use TT earthing or fancy EV chargers that have open-PEN fault mitigation built in.

[**] The regulations allow for just a single RCD 'layer' so long as it meets the specifications for adequate disconnection. They also recommend that folk test them every 6 months just in case one fails, but hardly anyone does that.

What he said …..at 8.30 on Saturday morning @pc1966 that’s impressive

It may be that you have no bonding on your water pipes. It could be there is some fault in the installation. What did the spark look at when he came? What did he do? Can you post pics of your fuse box and incoming power? In any event it seems that you (and family?) are in a potentially dangerous situation. Is it rented or...? Mmm forgot about it is the same if the power is off so default to (probably to you, no disrespect intended) incomprehensible explanation of @pc1966.

why is everybody's screen name preceded by a "@".
"I am not a number, I am a person" ?????

@telectrix comes from Twittering or one of the other millions of unsocial medias.

It alerts the user named, not sure if it works on here tho, you'll know possibly now.
It may need notifications turned on to get the alert.
@snowhead

Keeping it simple and making some assumptions, if three neighbouring houses are drawing 40,50 and 60 amps at the same time then 17 amps will be flowing on the neutral that is common to all of them. Greater differences can result in greater neutral current.
A lot of properties have neutral joined to earth. This join happens before the main switch.
Earth is not allowed to be switched, so everything bonded and metal in your house is connected to the neighbourhood Neutral at all times.

(The Neutral will usually have multiple little electrodes to earth on the supplier side to ‘drain away’ a lot of this current.)

It can be it possible to ‘feel’ the neutral current in the neighbourhood on anything that is earthed.

It’s more likely when standing on real earth but not impossible inside especially in bare foot.( A common question is regarding feeling a tingle when getting into an outdoor hot tub - it’s exactly the same reason.)

While this set of circumstances might explain it it’s worth having another go at getting it looked at to be sure.

Anyone know of sparks on here that are London-based who might be able to verify if the above is really the case, or if something odd is happening?

Could be next to some commercial/industrial units that are causing this through high draw equipment. I find it unlikely domestic usage would cause this, or at least very unusual. Personally I think the DNO may have missed something, it's possible. Although to be fair they do seem to know what they are doing when I see them in operation.

It's my own property and the DNO changed the main wire thats coming in to the property this morning but the problem continues. When the electrician removes the earth thats coming in from the outside it solves the problem but again that earth has to be connected. Please see attached pictures of the recently (moved outside) meter, fuse and the fusebox inside. If there's anyone in North London with experience that can come and have a look please contact me. Thank you.

You shouldn't be getting any shocks or tingling sensation, someone has missed the fault.

How long has the problem been going on?
Was the problem there before the meter was moved outside?
Has any other work been done inside or outside your house or at any of the neighbours or in the street outside recently?

Did your electrican or the DNO measure the voltage on the pipework?

Judging by the 1st photo at least you aren't paying for the electric for the shock, the meter is bypassed.
Where does the cable on the right go to, presumably the consumer unit (fuse box)?
Which cable did the DNO replace?

Bought the property last year and did a full refurbishment. The problem is only there when you stand barefoot on tiles or ground and touch the taps/radiators or water so it's very difficult to tell if the issue was there before the works. The problem has been going on for nearly a month now and yes the problem was there before the meter got moved outside. The electrician measured the pipework and can see that theres a low voltage 3-4 on the taps. DNO says that the readings of the main cable are just fine.

snowhead said:

You shouldn't be getting any shocks or tingling sensation, someone has missed the fault.

How long has the problem been going on?
Was the problem there before the meter was moved outside?
Has any other work been done inside or outside your house or at any of the neighbours or in the street outside recently?

Did your electrican or the DNO measure the voltage on the pipework?

Judging by the 1st photo at least you aren't paying for the electric for the shock, the meter is bypassed.
Where does the cable on the right go to, presumably the consumer unit (fuse box)?
Which cable did the DNO replace?

Click to expand...

So you are basically saying that the meter is not working cause the wrong wiring?
Correct.
DNO replaced the cable thats going from the meter outside to the fusebox inside (The cable on the right). We thought that maybe that cable was damaged during the refurbishment works but clearly that's not the case cause the problem continues.

As @snowhead says your meter is not connected to that outgoing cable.
Can you take the trunking lid off below the consumer unit because I suspect the armour of that cable is not earthed.

westward10 said:

As @snowhead says your meter is not connected to that outgoing cable.
Can you take the trunking lid off below the consumer unit because I suspect the armour of that cable is not earthed.

Click to expand...

Thank you for the clarification and i do understand now. Please see attached. I hope the pictures are clear enough?

If I wasn’t paying for electricity, I’d just put up with a slight tingle. Wear rubber shoes when on the tiles.

Why have they connected it like that? Direct off the fuse, not through the meter?

Is what they have done temporary.

I look after a Business Park & a few people reported a slight tingle when switching the light on in a corridor with a concrete floor. I did not experience a tingle. The only way I could measure the true voltage was by placing a wet cloth on the concrete with a metal plate on top. I tested between the metal light switch & the floor plate & I got around 4 volts. I changed the switch & it was okay. I guess the voltage was tracking through, although no visible signs of damage or excessive wear. The lighting circuit was on a RCD Protected Panel.

Electro-tech said:

I look after a Business Park & a few people reported a slight tingle when switching the light on in a corridor with a concrete floor. I did not experience a tingle. The only way I could measure the true voltage was by placing a wet cloth on the concrete with a metal plate on top. I tested between the metal light switch & the floor plate & I got around 4 volts. I changed the switch & it was okay. I guess the voltage was tracking through, although no visible signs of damage or excessive wear. The lighting circuit was on a RCD Protected Panel.

Click to expand...

Did you still get the tingles when the main power switch was switched off? Because that's the case with me.

Is the incoming water service plastic? You could have a a plastic section of pipe installed to isolate the pipework from both the dno and true earth if it's not.

MTerzi said:

Did you still get the tingles when the main power switch was switched off? Because that's the case with me.

Click to expand...

From memory, I did not test with power off. I know this isn't helping, just confirming what TimHoward quoted regarding True Earth.

Aaron b said:

Is the incoming water service plastic? You could have a a plastic section of pipe installed to isolate the pipework from both the dno and true earth if it's not.

Click to expand...

Looking at the earth bar in the CU it would suggest that the gas and water is bonded

@MTerzi are you saying the DNO installed that cable because if they did you need to be contacting them. For them to connect a cable like that is very bizarre, it isn't being metered.

The choice of a Hager board is good, but the installation of the SWA is awful!

Not only the really odd aspect of the meter being bypassed, but there is primary insulation exposed in the meter box and no apparent sign of the armour being earthed. Length is not obvious either, if it is under 3m so OK to directly connect, or longer so a switch-fuse should be there in the meter box (which would also allow an opportunity for a gland, as the metal CU did).

None of this would alter the OP's original issue, but it is a touch worrying to see.

The fact that you get the tingles with the main switch off means that your own installation is pretty much guaranteed not to be the cause. Post 2 by @pc1966 hits the most likely nail on the head, a difference between the incoming CNE voltage and local true earth. When you felt the tingles, were you standing on a concrete floor?

That cable from the meter box is utterly bonkers. Are you sure it was the DNO who installed it and not someone whose experience is in 'loft-based horticulture?' Armour floating, unsheathed cores exposed, Inadequate support, possibly no SF for >3m, and the minor detail of missing out the meter. Did one guy do the outside end and another the inside, so that they each thought the relevant meter was at the other end? I'm at a complete loss to explain it otherwise.