Search results

Well the inside of your fire hose is soft membrane tissue with a large surface area, not very much impedance. I wouldn't try it if you gave me boots that looked like 132kV bushings.

750V and 1.5kV overhead is more common than you think. In the UK we use it on most of our light rail systems. < 3kV is used for the OHLE on many non-express networks in mainline Europe. If you ever see the roof of a Class 373 Eurostar power car you will see the two pantographs - an MV one for...

Back to the original topic. If you ever speak with DNO people they will often tell you that its LV that they fear the most. 11kV and above tend to be arc risks - you get blown back as you approach the equipment. Also its worth noting that MV and HV equipment normally has several layers of safety...

The HSE do a nice handbook on electrical safety - with case studies full of gory stories. I remember one example of a poor arc welder working in the Glasgow ship yards. He was wading up to his waist in water and using a 50v arc welder. needless to say he touched the end of his welder and his...

I would never go though a formal test process at a notified body unless I'm reasonably satisfied that the product is going to pass. Pre-compliance is always the answer. I tend to find the technicians at the test houses very useful, Its best to be all ears in those places as at the end of the...

It was EN 60950. The UL standards are useful, and the american's tend to be more practical in their standards. However on this side of the pond its the EN standards that are listed in OJEU.

Having previously done impact testing to ensure compliance of an electrical product with electrical safety standards, its not actually that difficult to meet the mechanical requirements. Hence if you give a mains socket a good kicking you will often expose hazardous parts. I've not got the...

The additional requirement in amendment 3 requires an enclosure that is non combustible. No mention of electrical safety whatsoever. We earth the enclosure because we are obliged to do that, but not as a result of this amendment. If the enclosure was ceramic, and had an internal and separate...

I think I probably am. But I'm obviously being pedantic also. But a ceramic enclosure would tend to be preferable to metal for combustibility purposes. But then some ceramics have a reasonable moisture content and aren't as good an electrical insulator as they first appear - but normally far...

Hence I just thought I would play devils advocate and throw galvanised in there. The strict wording in the standards can sometimes bind you in your choice of design. Galvanised conduit that is properly bonded would on the face of it be as good as PVC (ok there is an additional failure mode)...

It provides double and/or reinforced protection if you close the doors and windows (except that the front door lock bridges that protection, but then these fittings are isolated from hazardous parts by the appropriate clearance and creep-age). I'm quite confident that a double cavity brick wall...

Would slightly defeat the object. My house is made out of bricks, which makes it a non-combustable enclosure.

Interesting point. All new CU's are fitted with RCD protection so a a DIYer meddling is most likely going to trip the RCD. However if the DIYer does something really stupid like disconnect the earthing connection to the Mains Earthing Block, all CPC's are now going to be bonded directly to the...

Its probably going to be tidier to keep the PVC to the new cable installation. Just to throw a spanner in the works, if it was a galvanised steel conduit instead of PVC, the conduit is solidly earthed and the gas pipe is also equipotentially bonded. Anybody see a hazard there from a gas...

I'm looking at this from an electrical perspective, but I am interested in the view of a Gas Safe engineer - hence posting here. BS6891:2005 8.16.2 Where installation pipes are not separated by electrical insulating material, they shall be spaced as follows: a) at least 150 mm away from...

I agree John and I think that the wording is poor. Plastics can be manufactured with flame retardants, but obviously any plastic will combust eventually. Die-cast aluminium is obviously also out of the question, aluminium burns well. But as John rightly points out, even Steel is combustible...

Since 1st January all newly installed Consumer Units must be metal. Even counter intuitively on a TT supply. Problems with fires in the plastic ones.

Well now were on amendment 3, our CU's all need to be non-combustible, which can only be achieved through the use of metal. If we were to see the term non-combustible with regards to such barriers then galvanised would probably be the only way to go. Wait and see for further amendments. Perhaps...

My original question wasn't about bonding, it was about clearance. I'll be using PVC conduit, otherwise if it was Galvanised conduit then perhaps it would be prudent to bond to the gas pipe. It wasn't written in the on site guide for S&G purposes.

Exactly, in the balance this installation would probably be safer unearthed then being earthed separately to its adjacent socket - or earthed but not bonded. If equipment already has a high impedance path to ground, its normally safer to leave it that way such that nobody can get a nasty shock...