I understand that the only changes to the latest 17th amendment CUs is the addition of SPDs, however I believe there are exceptions to the rule depending on the type of property and the number of occupants. So would a two bedroom bungalow with two occupants fall into the exception category?In the garage I am using PVC trunking to run cables round and to comply with the latest fire rating requirements I am using some metal inserts that support the cables. The problem with the cable clips is that they do not match the trunking perfectly requiring a slight modification to the trunking to get them to fit. This is dragging out the job a bit and I am looking into alternatives. What I am looking for is a recommended spacing within the trunking for whatever type of fire clips I use, surely it cannot be the same as the recommended spacing of the old plastic cable [email protected] 1:41. On Thursday, 18 July 2019 23:29:53 UTC+1, Tricky Dicky wrote: In the garage I am using PVC trunking.The fire retaining cable clips do not have to be within the trunking.Builder's perforated band round the outside of the trunking will support the cables (and trunking) in the event of a fire.Spacing has to be sufficient to stop the cables becoming an entanglement hazard.
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Along a wall every 1m or 1.5m may be sufficient, and each side of a doorway (more over a garage vehicular door).OwainRobin19.07.19 3:00. On 23:29, Tricky Dicky wrote: I understand that the only changes to the latest 17th amendment CUs is the addition of SPDs, however I believe there are exceptions to the rule depending on the type of property and the number of occupants. So would a two bedroom bungalow with two occupants fall into the exception category?With luck someone who really knows will be along i.d.c. With a simple,reassuring answer.In the meantime.while looking at a new CU here I depressed myself bylooking at Appendix B to the BEAMA guide (link below) which sets outwhat's involved in deciding if an SPD is needed. It hasan example which fits here to a T with the answer 'not a requirement'.Be warned though, Appendix B seriously confirmed my belief that the regsare getting beyond the capacity of the average sparks.There is (assuming you don't have an overhead supply) an exception for'for single dwelling units where the total value of the installationand equipment therein does not justify such protection and theconsequential losses are tolerable.' But that seems to me a bit of aminefield when it 'is further explained in IEC 60364-4-44 which statesthat overvoltage protection is not required for single dwelling unitswhere the total economic value of the electrical installation to beprotected is less than five times the economic value of the SPD locatedat the origin of the installation'. I suspect rather few homes don'thave a TV, PVR, washing machine, etc at risk from a surge worth morethan 5 times the cost of an SPD.And I was also left wondering how insurance companies would deal with ona claim for losses due to a power surge if no SPD was fitted post-18th.Want to see a risk assessment from a pro before paying out?-Robinreply-to address is (intended to be) validJohn Rumm19.07.19 5:12.
The 18th Edition Wiring Regulations BS7671:2018. Editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean. Other than a dwelling, a documented risk assessment determines that RCD protection is not necessary. A new Regulation 411.3.4 requires that, within domestic (household. The 18th Edition Wiring Regulations and the use of SPD’s (Surge Protection Devices) for Protection of Transient Over voltages from Lighting Strikes and Supply Switching Origins.
On 23:29, Tricky Dicky wrote: I understand that the only changes to the latest 17th amendment CUs is the addition of SPDs, however I believe there are exceptions to the rule depending on the type of property and the number of occupants. So would a two bedroom bungalow with two occupants fall into the exception category?For domestic its down to the owner to decide if its worth having.
In the garage I am using PVC trunking to run cables round and to comply with the latest fire rating requirements I am using some metal inserts that support the cables. The problem with the cable clips is that they do not match the trunking perfectly requiring a slight modification to the trunking to get them to fit. This is dragging out the job a bit and I am looking into alternatives. What I am looking for is a recommended spacing within the trunking for whatever type of fire clips I use, surely it cannot be the same as the recommended spacing of the old plastic cable clips?No, you can go wider on the clips. There seems to be no officialguidance, but common sense would suggest at least every 1.5m in generalcases and a bit closer over access routes.-Cheers,John./ Internode Ltd - - John Rumm - john(at)internode(dot)co(dot)uk /[email protected] 5:28.
Looks like an SPD will be fitted purely on the principle that we have electronic equipment whose value easily outweighs the cost of even the most costly SPD I have come across so far and what cost do you put on a human life?As for the fire safety clips I have very little surface wiring but I take it from replies so far that I can use standard plastic clips interspersed with metal clips at intervals between 1m and 1.5m. I have been using those expensive Thorsman ones Screwfix sell and find them unsatisfactory in that they do not grip the cables tight enough which slide through them quite easily the result is you cannot get the tension on the cable to produce nice straight runs.As far as the trunking is concerned at present I have 12m installed so at a spacing of 1m I am only talking at about 12 or thereabouts.
I might look at using builders band on the outside of the trunking still looking at the possibilities. Most of the available solutions do not seem to be designed to grip cables firmly but more provide loose support for the cables.Thanks for the advice so far, I am still open to any more suggestions.RichardThe Natural Philosopher19.07.19 21:16. On 20:53, Tricky Dicky wrote: Looks like an SPD will be fitted purely on the principle that we have electronic equipment whose value easily outweighs the cost of even the most costly SPD I have come across so far and what cost do you put on a human life?That sounds as false as insisting on windmills on the basis that theyMIGHT save CO2 emissions and those MIGHT be implicated in unpleasantclimate change.In my increasingly long life I have only ever seen surge damage in thecase of near (or direct) lightning strike.And I cant recall ANY of the damage being via the mains. Mains alreadyhad RF filters: Mains transformers won't propagate fast edged spikesand SMPSUS have fucking great caps to absorb itIn short surge protection is about as pointless as Russ Andrews $45000hifi cables.-Outside of a dog, a book is a man's best friend.
Inside of a dog it'stoo dark to read.Groucho [email protected] 23:13. On 20:53, Tricky Dicky wrote: Looks like an SPD will be fitted purely on the principle that we have electronic equipment whose value easily outweighs the cost of even the most costly SPD I have come across so farbut you also have to factor in the risk of a power surge causing harm.I've only lost 2 bits of kit in 30-odd years: a PVR and an ATX power supply.
and what cost do you put on a human life?That's been a routine job in cost-benefit appraisal for decades. Butit's true that many would disagree with eg NICE's use of about £30,000for a year of good quality life - especially when it's their life:)Tricky Dicky20.07.19 2:49. but you also have to factor in the risk of a power surge causing harm.I've only lost 2 bits of kit in 30-odd years: a PVR and an ATX power supply.The risks of power surges seems quite low, to my knowledge I have never experienced one certainly not one that has resulted in damage or injury. It seems that the IET is getting to the point of trying to eliminate any risk no matter how small. To be honest it seems more faff to do the CRL calculation and the risk assessment than to stomp up the money and the few minutes to fit the device.RichardAndy Burns20.07.19 4:25. Tricky Dicky wrote: The risks of power surges seems quite low, to my knowledge I have never experienced one certainly not one that has resulted in damage or injury. It seems that the IET is getting to the point of trying to eliminate any risk no matter how small.
On Saturday, 20 July 2019 10:49:21 UTC+1, Tricky Dicky wrote: but you also have to factor in the risk of a power surge causing harm. I've only lost 2 bits of kit in 30-odd years: a PVR and an ATX power supply. The risks of power surges seems quite low, to my knowledge I have never experienced one certainly not one that has resulted in damage or injury. It seems that the IET is getting to the point of trying to eliminate any risk no matter how small.They're creating a risk many times the size of any risk that might be reduced.
To be honest it seems more faff to do the CRL calculation and the risk assessment than to stomp up the money and the few minutes to fit the device. RichardEven less faff to not waste the time.ARW20.07.19 9:39.
443.4 continues with a catch-all, after (i) through (iv) are satisfied, by detailing an exception to the requirement being 'single dwelling units where the total value of the installation and equipment therein does not justify such protection'. Personally I can't see many exceptions, when considering the small price of installing this protection, ultimately this would be the insurer's call and I imagine it will not be long before buildings and contents policies stipulate SPDs as a requirement in their T&Cs. 443.4 continues with a catch-all, after (i) through (iv) are satisfied, by detailing an exception to the requirement being 'single dwelling units where the total value of the installation and equipment therein does not justify such protection'. Personally I can't see many exceptions, when considering the small price of installing this protection, ultimately this would be the insurer's call and I imagine it will not be long before buildings and contents policies stipulate SPDs as a requirement in their T&Cs. I fitted an spd in the CU in my flat when i changed it over to all rcbo's Hager SPD's not that big compared to some. Has a type c 125A MCB then SPD modules the size of standard mcb, its a sort of carrier where the spd part can be popped out and replaced if required.Back when I fitted it, it came to £68.the mcb links to spd via a piece of 6mm brown.Fitted it as the people who wired my flat (new build) didnt fit one, the risk assessment said one was needed and coincidentally they came back to fit them in other flats after i raised it with freeholder!
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Has anyone actually carried out the calculation assuming a few figures that you aren’t going to know like the length the supply cable to the DNO TX? Has anyone actually carried out the calculation assuming a few figures that you aren’t going to know like the length the supply cable to the DNO TX? So you think we can only realistically install type 2 and type 3 in non domestic installations as with a type 1 you would require an LPZ in place which I understand would require a risk assessment done for lighting strikes on the building, something that I couldn’t advise on and would struggle to put across to a client to justify needing one.Normally larger new build commercial jobs where the design aspect is out of the installers duties as when done by a consultant it would be specifie (lighting protection). So you think we can only realistically install type 2 and type 3 in non domestic installations as with a type 1 you would require an LPZ in place which I understand would require a risk assessment done for lighting strikes on the building, something that I couldn’t advise on and would struggle to put across to a client to justify needing one.Normally larger new build commercial jobs where the design aspect is out of the installers duties as when done by a consultant it would be specifie (lighting protection).
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