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I quoted for that job using using these: http://www.tonesties.co.uk/Product/3051/serrated-washers.aspx and these; http://www.tonesties.co.uk/Product/3048/brass-earth-tags.aspx A bit cheaper. Piranha nuts are good, but not so good that they justify that price difference for an MI...

It depend what you mean by 'satisfy the impact properties'. The cables, conduits and trunkings listed do not prevent damage due to impact, and do not have to resist penetration. What they do have to do is stay intact long enough for a fault to clear after penetration - so if the standard...

Section 522 lists various cables and their related standards - it requires that the cable used complies with one of the listed standards. Any cable not included there would have to be tested for compliance against one of the given standards. The only alternative would be to invoke...

Copper and aluminium conduit have been used in the past. They would both probably comply with BS EN 61386 as this applies to all conduit including plastic. To meet section 522 (impact) the conduit must meet the requirements of BS 7671 for a protective conductor. Copper and aluminium could...

No more than about 5 kA at the DB intake point. Each sub-stations has a pair of 1600 kVA transformers operating separately so your maximum fault level at the sub-station is under 40kA (assuming Zpu ~ 0.06 - which is fairly common for that size transformer). Each distribution circuit is...

I discovered this on a Saturday afternoon during part of a rolling PIR programme I do for the site owner. The installation is large (7 * 11kV / 400 V sub-stations and around 5000 final circuits). The building has a large steel frame and the sub-station related to this DB is roof mounted...

Lectrician has it :D. This is a Dorman Smith DB in a large 'high class' installation carried out by one of the largest contractors in the country. What makes it worse is that it was installed about 6 years ago and other contractors have worked on it since :shock: Of course the test...

Visual inspection - try this DB - two views of the same DB - can you spot the most significant error :D.

Read this http://www.hse.gov.uk/fod/infodocs/483_27.pdf Note Paragraph 5 - this is why sub-station doors usually used to open outwards :D. It allows the pressure wave to be released and blows the engineers body parts outside where they are easier to pick up. :shock:

This is a C & G exam - they don't do deep thought :D. Check out 612.4.1 and 612.4.2 and note that the words in the regulations include 'be confirmed by'. Sometimes the incorrect answer is given because the candidate assumes that the examiner knows the subject :D:D EDIT typo

Using an RCD as a means of fault current protection on a circuit with no circuit protective conductor (earth wire) - is specifically prohibited by BS 7671 [531.2.5] - if that circuit would normally be expected to have a circuit protective conductor. So you should take the advice given by...

I am no expert on heating systems but you should consider the following. Storage heaters receive their charge of energy during the off-peak period and store enough of it as heat for latter use throughout the rest of the day. They are usually on an off-peak tariff. It appears to me that...

It became SparkyResurrection Try here http://sparkyr.multiply.com/ I don't know if it still has past papers etc.

First you should identify which, if any, regulation(s) address this issue. You will not find any specific to cooking appliances only, they went out long ago. We did have [476-03-04] in the 16th Edition but that did not make it to the 17th Edition. You might take a look at [537.1]...

Well a quick read of that should convince anyone that the best solution is to avoid the problem. I would just make sure the insulation is not in direct contact with the cable where it passes through :D.

Why don't you ask them - try here first http://openlibrary.org/a/OL1337684A/Electrical_Research_Association.

Probably nothing - but I am like that :D. Table 52A is based on research by the ERA and was introduced in the first release (Red Cover) of the 16th Edition. It had always been assumed that cables covered by thermal insulation over short distances would not be subject to stress as the...