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rasklit
Thats my problem , the inverter is floating
20A DP switches on a 32A circuit anyone?
123 your spot on.It isn't ideal what he has done, it was just to prove a point between sparks. The bank of sockets is upstream from the RCD hence the N-E link was placed there as the N-E link.
Ideally the N-E link would be in the inverter as it is source of supply and ought to have an earth rod tying it down to mother earth. As you may find with small sources they are often left electrically floating or "separate".
123 your spot on.It isn't ideal what he has done, it was just to prove a point between sparks. The bank of sockets is upstream from the RCD hence the N-E link was placed there as the N-E link.
Ideally the N-E link would be in the inverter as it is source of supply and ought to have an earth rod tying it down to mother earth. As you may find with small sources they are often left electrically floating or "separate".
Not quite the same. All lamps/bulbs should have internal fuses so if there is ionisation when the bulb blows it will take out the fuse in the bulb. I realise some bulbs from china don't comply but in theroy they should have fuses built into the bulb.20A DP switches on a 32A circuit anyone?
That's no different to 2A sockets on a 6A lighting circuit: perfectly acceptable as long as the load drawn is 2A or less.
In the main the use of underside cable to feed the protective device is for where we take a tapping from a bus bar unless the bottle fuse system is used one does not really have an option. However the same rule does allow one to take a spur from a ring main. However the 3 meter rule still applies.
It gets worse, recently I was in an office welfare area and the double socket had two adapters and plugged in were two 3KW kettles, dishwasher, fridge and microwave, with a total possible load of around 9.5KW. This was running on a 2.5mm fp200 spur on a ring main which was also powering the remainder of the office, and had 'never caused a problem'
I have argued in the past there is nothing in 433.2.2 which says this does not apply to a ring circuit and spur so I feel it does apply.
Long spurs will have a problem complying with the loop impedance requirements and I have also argued that the line - neutral impedance is also important both to ensure the magnetic part of a MCB can operate and also volt drop.
The other problem is where the impedance is below 1.44 ohms as with 16 amp radials is extension leads with normal 13A fuses would need to have less than zero resistance for it to rupture within the prescribed time.
The half conversion to Europe's lower standards can have some unexpected results. One items which I think we really need is a FCU able to take a 16A fuse so ovens, washing machines etc designed for Europe can be used in the UK without a part re-wire.
As to washing machine I can't see the difference in a machine which is fixed within a space left for it and building it into a cupboard they are to all intent and purpose fixed. So washing machine (with the exception of old top loading twin tub), tumble drier, dishwasher, oven, and immersion heater all come under the same rules. Appendix 15 refers to regulation 433.1 and points out items over 2kW should have their own dedicated radial circuit.
I have questioned many times the idea of having 20A switches connected to a ring and supplying fixed items in the kitchen area. Since we should really wire the fridge and freezer in ali-tube so RCD protection is not required one has to question if rather than two 2.5mm cables feeding the grid switch should each switch in the bank have it's own feed?
It gets worse, recently I was in an office welfare area and the double socket had two adapters and plugged in were two 3KW kettles, dishwasher, fridge and microwave, with a total possible load of around 9.5KW. This was running on a 2.5mm fp200 spur on a ring main which was also powering the remainder of the office, and had 'never caused a problem'
I had to replace a spur which had a single to double adaptor double socket on the end of it. Plugged into it was a 2 way block. It was supplying a washing machine, dishwasher and a tumble drier
Got a little bit warm and melted the socket. Wire seemed fine tho.
In essence, a double socket isn't meant to have two 13A loads on it, as others will agree the washing machine tumble drier scenario finishes off a lot of double sockets!
I think 20A DP switches are built to a BS number which is not on the list of permitted BS numbers in the reg for ring final circuits.
As I see it, whether or not 433.2.2 applies at all in this situation depends upon whether one regards the transition from the ring to the spur cable as "a reduction in CSA".But do the regs actually place a 3m limit on 2.5mm spurs on ring mains? I have certainly seen many which are well over 3m in length.
You link it's "neutral" to earth and it's no longer floating.Thats my problem , the inverter is floating
You link it's "neutral" to earth and it's no longer floating.Thats my problem , the inverter is floating
As to your other thread, you got it locked a bit quick. The inverter would need it's own reliable earth*, and for the RCD to offer any protection AND for safety since the loads will all be single pole switched, you'd want to link it's neutral to earth.
* The incoming MET would be an obvious place - but bear in mind that if the supply gets disconnected, then so does your earth. The difference is that with the normal mains supply, if the supply is off then you have no power so lack of earth is a moot point.
The obvious course of action is to consult a qualified electrician - but I know quite a few who would respond with
No it wasn't.Under 16th it was permissable to use a ... 16A mcb off a ring.
BS EN 60669.I think 20A DP switches are built to a BS number which is not on the list of permitted BS numbers in the reg for ring final circuits.
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