Dedicated fuse spur

[bulby]

Hi
Ive been asked to quote for spur spurs at top of stairs taken from upstairs ring main, most of the properties ive inspected are on tns system, i have my 2392 but this will be the first electrical work ive done in 4 years. Im having problems with the testing results for my minor works certs, i could do with a bit of refreshing, the db for these jobs are mostly bs3036 fuses and alot without bonding, some have with 6mm, do i have to upgrade these of can i recommend upgrading ? acording to my minor works i need zs reading, do i need ze ? and can i take my ze and zs and calculate R1+R2


All help will be much appreicated

[ian2]

No you dont need the Ze and you can calculate the R1+R2, however taking the reading is the best if only for your own peace of mind. If you do any work you must fill in the limitations or you will become liable for the whole installation. Also there is a box for any comments on the installation fill this in about the earthing. If any serious departures ie. no main or under sized equipotential bonding then these are a code1 and should be brought to the attention of the owner/occupier and no work should be done as you will be classed as the skilled person and again be liable.

hope this helps.

[bulby]

From what i have seen its the gas and water bonding that seem to be undersized, do i have to upgrade them to 10mm or can i just put them under recommendations ? also when it asks on the cert for wiring method is there a table somewhere for clipped diect , in wall etc...

[Slowspark]

I would definately recommend that the client have a full periodic inspection report of the property. Sounds like there hasn't been upgrading for quite a while and if there is undersized (or no) bonding and no RCD protection I would say it's well overdue.

I would be unhappy walking away from such an installation without pointing out at least the main points concerning electrical safety and complying with the current regs. As Ian2 says- record testing limitations and make comments on departures to cover yourself.

Zs readings will give you a good idea of the existing earthing. I would also try to inspect the bonding terminations for signs of thermal damage. Neutral/earth faults on non RCD installations can cause currents to earth through the bonding. On older installations I've even seen lighting circuits where lamps have been connected between live and earth so be careful when disconnecting any bonding!

This said- undersized (6mm) bonding could be given a code 2 or 4 according to the NicEic's Snags and Solutions book.