Old Cabling Upgrade

[tomsw18]

We're currently tendering for a project where the client has requested a number of DBs to be upgraded in a commercial building. The installation is around 5o years old. Site survey isn't until next week so we haven't been to look yet and we don't know what records they have or when it was last inspected, etc. (or why  their usual company isn't doing it).

I guess in theory if we tested everything prior to removals and it checked out, there isn't a mandatory requirement to change the cabling but what regulations would you highlight to get them to consider this?

 

[binky]

simple answer is test and ascertain what state the cable is in. The recommendation is that cable that passes inspection is good for another 5-10years. Beyond that there is no reg that says cable should be changed because it is old, however it may be worth digging out cable lifetime advice. Can't remember were I saw that info last, but something like 2.5mm being used at full tilt 24/7/365 could have a lifespan as short as 5 years, or 50 years under light domestic use. The only other thing you can do is advise the client that the cable is old and likely to become unreliable soon, but again, testing would indicate that. 

 

[Evans Electric]

Wouldn't that be the remit of an  engineer . ?    A 1970  installation  then ,   that,s in the day of  using the conduit & trunking as the earth  for a start .  

There is'nt a requirement to change the cabling if the testing proves OK  .    Fitting new boards would  of course answer the  lack of RCD s .  

When you say  "client"   ...is that the building owning  customer  or is it a contractor looking to sub it out to you. ?  

 

[tomsw18]

Wouldn't that be the remit of an  engineer . ?    A 1970  installation  then ,   that,s in the day of  using the conduit & trunking as the earth  for a start .  

There is'nt a requirement to change the cabling if the testing proves OK  .    Fitting new boards would  of course answer the  lack of RCD s .  

When you say  "client"   ...is that the building owning  customer  or is it a contractor looking to sub it out to you. ?  

Client who I'm talking to is the Financial Director of the business. Unsure if they're the building owner yet. I'll go into the finer details during the site visit. 

 

[binky]

Client who I'm talking to is the Financial Director of the business. Unsure if they're the building owner yet. I'll go into the finer details during the site visit. 

make sure you get payment terms agreed, in writing / email. A lot of finance directors like to think 56 days is acceptable...

 

[phil d]

I had a chuckle reading this, many years ago we'd tested a large office block over the road from the Manchester Arndale centre and told them in no uncertain terms that the wiring was well past it's date, a lot of it was in VIR. They had been having a lot of issues, hence the reason for getting us in, the trouble was that the owners of the building, a large legal fim, didn't like the price of getting it rewired, then shortly afterwards we had the bombings on the Arndale. Not long afterwards we were again contacted by this company, several buildings including theirs had suffered window damage in the blast and they wondered if it was possible for us to right a report for them stating that their electrical problems were directly attributable to the bomb blast. They were less than happy when we wrote back to them stating that not only would it be stretching the bounds of reality, but could also damage our reputation if we were to do this, considering the bomb blast had done no more damage than blow out a couple of large windows.

 

[Evans Electric]

And that was from a large legal firm   !!!

 

[Phoenix]

I thought the trick was to come up with some wording that almost does what they ask for, without telling any direct untruths

"Following the incident, we measured the insulation resistance of many cables on the affected side of the building and found they measured low enough to be considered defective, it is known that this type of cable, over time dries out, but even in this state, will continue to provide service for a good number of years, but can fail instantly if moved (modern plastic based cables offer increased performance and do not generally fail in this manner). Is is possible that vibrations from the incident, being of serveral orders of magnatude greater than that which the building would be exposed to on a day to day basis has triggered the cable failures which occured immediatly afterwards, there may also be further instances where failures may occur in future months caused by damage which is not yet known."

You then price them up for a rewire at a bit higher than normal rate