I think that you already know the answer!

The cabling provided by the DNO falls outside the scope of  BS 7671. Is it your intention to notify the DNO of this observation? The DNO maintains specific codes for reporting. I suppose you have to ask yourself, In your professional judgment, does this situation present an immediate danger to the consumer?

The lower type of sprung clamp ("Permagrip" TM or similar) was designed for lead services, and unlike a BS951 is supposed to assert a near constant force without damaging the lead sheath, and  is quite common here (Hants)The more modern equivalent is a spiral of spring steel that combines the worst attributes of an open corned beef can and a broken clock spring the so called 'constant force spring'

The essential idea of clamping the service cable with a bit of yield to avoid digging into the lead is the same.

Normally when updating the original bare imperial earth to the modern plastic covered stuff either solid green pre 1970 or green/yellow thereafter we try and get all the strands to be captive, but 5/7 isn't too bad I suppose 

The upper one looks like builders band and may not even be a DNO official connection.

However, if it survives the pull test and the Zs looks good, neither requires urgent attention, there is far worse in service.

Note that  if it fails some DNOs will tell you to convert to TT or request that you pay for a new supply cable.

M

The upper one looks like builders band

It does, although I think I can see a hint of green in a few places where it's been bent - which might suggest it's tinned copper perforated strip - which might have been the sort of thing Electricity Board types might have had in the bottom of their tool boxes once upon a time.

From a current carrying point of view, the float shape (lots of surface area) and the extra holes, would actually make it rather efficient thermally - so it might be good for a bit more than its simple c.s.a. might suggest.

  - Andy.

Thank you for the replies. For more context, photo 1 is a property in the South East that was built circa 1960 and photo 2 is a property in the same area but built late 70's early 80's.

It certainly has the tinned copper / original look. Hopefully the DNO can clarify as I think there may be more.

Despite my slightly flippant note the other day, personally I'd not blink at re-doing the clamp one to get all the strands under the jaws, or using a suitable lug or pin  crimp if upgrading to a larger gauge of earth cable that was not an easy fit.

pin crimp idea for fat wires into thin terminals - other designs are available...

The flat band one I'd be a bit more cautious with - I suppose it may be official, especially if it is tinned copper, but, well 'yuk'. I think if you are obliged to work on it, then you are right to seek DNO advice.

If the DNO do decide it is worth coming to look at it, could you let us know what they say, please, for future reference as it were.

Mike

Thank you for the pin-crimp advice, I have passed it on to the electrician involved. I am hoping to visit the same area next week and see if any other properties have the same type of connection. I suspect I will find a few more which should hopefully help me in dealing with the DNO. I will post their response.