OLEV Installation Auditor problems

Positive earth isn't it?

I thought that one line was at earth potential with a phone pair.

It'll be referenced to earth at the Exchange - but that could be miles away - I doubt that'll make much difference at the far end of a long thin wire. SPD effectiveness can be much reduced even after 10m.

   - Andy.

To be honest I am surprised the consumer unit in the video did not already have a SPD installed.

There was a brief mention of it having Type AC RCDs, but then there’s an odd comment about the SWA cable not having RCD protection, which it did not need as the EV charger has a RCD built into it, but it was red flagged in the audit. In the video there’s a spare RCD on top of the consumer so I assume the RCD has been replaced.

This particular consumer unit is a Hager “Hi-integrity” consumer unit, next to the main switch is a RCBO supplying an outbuilding, then the remaining circuits are divided between two RCDs with an individual MCB for each circuit.

If I had installed that consumer unit in the last four years or so I probably would have bought it from the wholesaler with the main switch, a SPD and two Type AC RCDs already installed, upgrading the RCDs is not an issue other than they have to be paid for as the wholesaler has them in stock, as they do all the other devices.

When I installed it I would have probably left the spare way as a non-RCD protected way, so any new circuit could be protected by either a MCB, RCBO or AFDD without altering the layout of any of the other circuits or having to alter their protective devices, indeed I would have probably pushed all the existing devices over to the left apart from the outbuilding RCBO, then replaced the non-RCD busbar to allow the new circuit connected to it.

This really should have an easy addition to the installation seeing as the consumer unit was installed so recently, it’s not like working on the old stuff I am used to, some of which is pre-war.

So, there seems to be conflicting comments:

• The SWA cable was not RCD protected, when it seems it actually was, but did not need to be. So if that was the case the the auditor is wrong.
• The EV charging equipment was protected by a Type AC RCD, if it was then it would seem the auditors comment was correct and it was an issue that should have been dealt with at the time of the installation.

All the stuff about circuit and main protective bonding conductor identification is not justifiable.

The issues about the lack of SPD protection should have been highlighted in the quote that was submitted to OZEV for the grant approval.

The picture shows what is sometimes called a PABX Master. It is intended for an office environment after a PABX where the spark gap arrestor would have been on the incoming line. The pcb has the location of the spark gap arrestor shown as SP1

Clive

Zoomup said:

Money makes the world go around. BT sockets already have an arrestor inbuilt. An old example....

https://www.ebay.co.uk/itm/221612544427

Z.

Whilst it WAS true that your phone socket DID have an arrestor (at least between lines), the NTE5 outlets do NOT have the arrestor in. The cheaper cost arrestors affect VDSL line speed, and therefore were not included in those outlets.

However, even if you have an older outlet with an arrestor (most are swapped out when you go to VDSL2 to achieve the line speed required), that isn't guaranteed to protect stuff connected to your home network, because to do that you'd need SPDs between phone lines and local PE of your mains supply (the MET preferably).

I have personally seen the result of a direct lightning strike on a 70s brick and tile house. Some bricks were actually cracked right through on the outside. Also some decorative fairy lights that were around an upstairs bedhead vaporised and caused black marks on the wall paper. I do not believe that such an incident could have been mitigated by any small device in a plastic box within the electrical installation. Only a comprehensive lightning protection system could have lessened the damaging effects here.

Z.

Speed before safety these days then? A bit like removing car seat belts to lighten them.

Z.

https://www.britishtelephones.com/lightng.htm

Z.

'Phones are cheap to replace. It is more expensive installing prevention than replacing a cheap phone.

https://www.britishtelephones.com/lightng.htm

Z.

But SPDs aren't supposed to protect electrical equipment from a direct strike - they're supposed to protect them from damage or degradation from a strike at the other end your street or whatever. Type 1 SPDs are useful in a direct strike - but only to temporarily equipotentially bond the live conductors to the metalwork of the house, reducing the risk of a flash starting a fire. (They still won't protect your electronics in that scenario.)