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Ring main tripping problems

Discussion in 'Home Cinema Building DIY' started by dunks517, Jul 6, 2008.

  1. dunks517

    dunks517 Active Member

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    The ring main in the house keeps tripping, sometimes several times a day and often between 2215 & 2230. There is obviously a problem and it may be with the power supply in the hub.

    There is a double socket in there and I have connected a 8 socket belkin extender to each socket.

    I have the following connected:

    PC
    PS3
    Sky HD
    Amp
    Wifi Router
    Loft box
    DVD player
    network switch
    Printer
    4 external hard drives

    Is that too much for one double socket?

    What could I do?

    a. Run a spur to create 4 sockets?

    b. Place a stronger fuse in the fusebox?

    c. remove the router,

    d. Place the hdds in a NAS in another room



    Please help?
    Last edited: Jul 6, 2008
  2. Gary Lightfoot

    Gary Lightfoot Active Member

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    Is it just the circuit breaker for the ring main that's tripping and is it a plain circuit breaker or an RCCD? One double socket can take (in theory) 26 amps, 13 amps per socket. The Belkin extender will be fitted with a 13 amp fuse so if anything draws more than 13 amps the plug fuse will go, not the breaker. Are you sure it's a ring main and not a radial with a 15 or 20 amp breaker? If the breaker is an RCCD then it will also trip if there is any current going down to earth, and that only needs to be greater than 30 milliamps to do it.

    If the total current is exceeding the breaker rating (32amp?) then it's an overload and the breaker is doing it's job. If you increase the breaker rating the cable will melt before the breaker has a chance to trip, so don't uprate the breaker; it's designed to trip and protect the cable from overheating.

    I wouldn't have thought that the kit you list would be drawing more than 32 amps (you may be able to find out by reading the plates on the kit & see what the current or wattage is), so it's possible that something could be going faulty.

    If you can place one of those bits of kit onto another ring main in the house, you may be able to find which one is tripping the breaker (it may trip the other ring main breaker). It doesn't happen when someone turns the kettle on does it?

    Gary
  3. dunks517

    dunks517 Active Member

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    Gary, In laymans terms we have 2 fuse units - 1 for the lighting and one for the power circuits, when the power trips it is not a circuit for example the study or lounge but it is the the main switch for the power side and this cuts of all power sockets in the house. I shall take a photo of the board tomorrow.


    As it is the main switch that goes it could be anything! Would X10 cause this?

    Duncs
    Last edited: Jul 6, 2008
  4. Gary Lightfoot

    Gary Lightfoot Active Member

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    Sounds like a split load board with the power being fed via an RCCD. It could be anything doing it (earth leakage), but quite often it can be something like a fridge or a loose wire in a socket (a friends washing machine would trip out his RCCD and that tuned out to be the wiring in the socket). The main power RCCD looks at the current going out via the live and compares it to the current coming back via the neutral. If the difference is greater than 30ma then some must be going out via the earth (like someone touching a live conductor) and that will cause an imbalance in the RCCD so it will trip.

    I think the only way to isolate it is to try unplugging one item at a time and leave it unplugged to see if the tripping stops (and that could mean trying everything that's connected to the power side). Tricky to do with things like a fridge though. Do you have any dodgy looking leads going to any appliances - leads with the wires showing as they go into plugs or any with nicks in for example? Try wiggling the leads to things that are plugged in and see if you get a trip.

    Does it always do it at the same time of night or can it sometimes be at any time? I wonder if you can narrow it down to something that's only being used at that time of night.

    Gary
  5. hornydragon

    hornydragon Active Member

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    The time seems odd you dont have any timer controlled lights connected to a 3 pin socket do you? IF its dropping the whole side of the board down at a specific time regularly i would put money on it being a dodgy appliance somewhere are you runing X10? could be a dodgy module are you blowing bulbs in the lighting?
  6. dunks517

    dunks517 Active Member

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    I have 6 X10 plugin light modules around the house, but currently do not have the CM11u setup so the lights are via remote only. I'm not blowing bulbs as it is only on the power ring main not the lighting. I now have commenced unplugging items later in the evenings to se what the cause may be. It may take some time...

    I thought it could be either the X10, combi boiler, freezer, wine cooler or even the septic tank if not in the hub, the common theme is that it happens at night around 2215! Sherlock where are you?
  7. Gary Lightfoot

    Gary Lightfoot Active Member

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    What happens during the ITV 10:00pm newsbreak? :)

    Gary
  8. ZippyCat

    ZippyCat Member

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    Hi Gary,

    Believe it or not a double socket is only rated at 13A in total not 2 x 13A, this is prescribed in BS 1363 and can be derived by looking at BS 7671/ 16th/17th Editions. In simplistic terms you can have 10A on one socket but only a ‘theoretical’ maximum of 3A on the other. Realistically you would be able to draw more than 13A in total, as manufacturers will over engineer to ensure compliance. It would not be advisable for example, to connect a washing machine and a separate tumbler dryer to the same double socket (even with diversity taken into account); it would be better to use two separate single sockets.

    With regards to Dunks’ problem it could be any number of things. I would do what has been suggested above and check all the wiring to each appliance first; failing that I would do the obvious and get a spark in to check. :)
  9. dunks517

    dunks517 Active Member

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    2206 tonight in the middle of GTA IV!!
  10. Gary Lightfoot

    Gary Lightfoot Active Member

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    Hi Zippy,

    Wow. Joe Public doesn't know that so what's to stop them from putting in two appliances or even two extension leads loaded up to the hilt? It makes sense to ensure the socket can take 26 amps otherwise there could be a risk of fire from over loaded sockets with all the electrical goods people own these days (I know diversity is meant to take this into account like rings on an electric oven are assumed to never all be on at the same time, but even so). I've even heard Part P qualified electricians state the 26a figure so it just goes to show how many people are actually aware of that. Is there anything definitive in the regs or elsewhere that mention that safety aspect with regards to fitting double socket outlets in utility rooms for example? I think I seem to remember something about fitting single SO's in certain situations rather than doubles so wonder if that's what it was referring to (or did I dream that??).

    Cheers

    Gary
  11. MarkP80

    MarkP80 Member

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    - I'll second that. I bet there's a very high proportion of households have a washing machine and tumble dryer plugged into a double socket in kitchens/utilities/garages all over the country. Bit of a worry!

    MarkP
  12. hornydragon

    hornydragon Active Member

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    very few appliances pull even close to 13A and even then its a peak not a constant, Having a lot of devices connected isnt a big issue but bare in mind the Supply Fuse to most homes which have 20 double sockets is normall 100A or in many cases 60A so if the whole house pulls more than60/100A the incoming fuse can blow. (this has to be replaced by the board not a spark!) but they rarely go the board is designed do go first IT is worth checing that the breakers for each circuit are correctly sized.
  13. Mark Grant

    Mark Grant Member

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    Do you have a security floodlight with a photocell or PIR that could activate at around 22:00 as it gets dark ?

    Mark.
  14. ZippyCat

    ZippyCat Member

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    It would be down to the designer to use a degree of judgement when locating sockets i.e. anticipate the likely load and adapt the design to suit. From a professional point of view I would only ever recommend single socket outlets to supply washing machines and tumble dryers, as this takes the ability to overload the socket away from the end user who wouldn’t reasonable be expected to know this.

    I’m sure most major manufacturers such as MK or Legrand would over-design to 26A, but it would not be reasonable to apply this to all manufacturers blindly; they only need to comply with BS 1363 so why go through the expense of adding additional copper?

    I’m sure a large percentage of electricians are unaware of the statutory requirements, but without referencing to BS 1363 it could be derived from the IEE Wiring Regulations. For example, you can spur off a ring final circuit once at each node to connect to either a single or double socket outlet without needing to limit the current to a maximum of 13A. If you decided to continue this to a second socket, a current limiting device is required to prevent the two sockets drawing in excess of 13A. If a double socket was rated at 26A you would not be permitted to even spur off once in the first case without limiting the current. :)
  15. dunks517

    dunks517 Active Member

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    I turned everything off in the hub bar the amp and SkyHD box and no power cut:clap:.

    What are my options apart from the least desirable of ripping the ceiling down to run another circuit?

    The hub is in a dead space next to the Utility room I can run one of the extenders to a socket in there, all that is required is to chop the plug and drill a small hole behind the washing machine (The utility room is on a different fuse than the office and hub).

    Workable?

    Or would I be able to run a spur of this double socket but I don't suppose that will help as the loading will be the same.

    Thanks for all your advice so far.

    One last thing, would the power cuts have contributed to the kanckering of the pc's motherboard and a fragging of an external hard drive? Time for a UPS me thinks.

    Cheers

    Duncs
  16. jjbull

    jjbull Member

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    couldnt you keep trying different things plugged in just in case it is one of the appliances
  17. dunks517

    dunks517 Active Member

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    That's what I'm doing, tonight I'll unplug 2 different appliances to fathom this one out Personally I think that the socket is overloaded.

    Duncs
  18. dunks517

    dunks517 Active Member

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    Update: I have removed the 3 external harddrive from the system and no power cut last night either!! :clap:
  19. Gary Lightfoot

    Gary Lightfoot Active Member

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    Hi Zippy,

    I've had a look at the back of some double sockets which I have lying around, and sure enough they all say 13A - but that could be because the spec is per single socket (so each socket is 13A making a total of 26A). The wikipedia entry for BS1363 seems to suggests that it's the plug that is limiting the load, not the socket itself, since most of the text seems to revolve around the plug. Even if you read the text knowing that 13A is the limit (for a double socket) it's very hard to actually get the spec to tell you that.

    Thing is I could see how that can be interpreted as one double drawing 26A being OK on 2.5mm T&E because the cable can take 27A (IIRC) if clipped correctly, so adding another would potentially put the cable in danger. Limiting the current is the obvious thing to do. Radials are usually 20A for example so you'd think the same principle was being applied there. 26A is fine for a double because the circuit is a ring.

    It's terribly ambiguous and you would think the regs would make the 13A limitation known within its' text more clearly if that was the case, especially as much of BS1363 seems to refer to plugs rather than S/Os (and the BS1363 socket info appears to suggest it's more of a receptacle/safety spec rather than for current carrying capacity). The fact you say that you're sure a large percentage of electricians are unaware of it proves the point. Diversity seems to be the safety factor rather than anything else if 13A for a double is the case.

    Do you have a link or can you reference something that I could look at that states it definitively?

    Thanks

    Gary
  20. Gary Lightfoot

    Gary Lightfoot Active Member

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    Getting closer then. :)

    Maybe you can now add one external drive into the system for a few days and see if that trips the breaker. If it doesn't, remove it and add another for a few days etc. With any luck you'll find it's only one that causes the trip.

    Still seems odd that it does it at the same time every night though. Any ideas why an external hard drive would do that? Are they all turned on at the same time during the day? Perhaps it develops a fault after it's been on for a certain period of time and it gets sufficiently hot for the transformer to start to break down.

    Gary
  21. dunks517

    dunks517 Active Member

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    Gary, I lost you at 'I've had a look at the back of some double sockets'

    So, If I add up the total 'ampage' of all items connected to the socket and ensure that they don't go much greater than 13 amps (you mention a bit of over engineering) for the double socket I should be ok?

    In the light of the fact the power hasn't tripped since I reduced the load on the socket I think that removing some items may have helped. :smashin:

    Finger Crossed!

    I just need to sort out the HDMI handshake problems on the amp now - I wish Genserve would reply to my emails. :mad:
  22. dunks517

    dunks517 Active Member

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    They tend to be on 24/7, I've ordered a Cat5e to USB connector to put them in another room.
  23. Gary Lightfoot

    Gary Lightfoot Active Member

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    I don't think your problem is over current since the main RCCD breaker is tripping and not the ring main breaker (you said you lose all your power circuits). It sounds like one of the hard drives has an earth leakage problem. If you have three of them, and it can be any one of them, just adding them one at a time might isolate which one it is. Still seems strange that it trips at the same time at night though, especially if they're on 24/7.

    If it's the hard drive that's causing the problem with an earth fault, putting it in another room won't resolve the issue since it will still cause the main breaker to trip but via a different ring circuit. If you can trace it to just one external drive, then you may have to replace powersupply that feeds the box it's housed in.

    Gary
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  24. KelvinS1965

    KelvinS1965 Well-Known Member

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    RE the hard drives causing the trip at a particular time....have you got an Anti Virus set to scan, updates downloading or maybe some other background maintenance is happening, like a backup or such like? If you have an RCD socket adapter (like for plugging a lawnmower into for example) you could plug a suspect drive into through that then I should just trip the adaptor...if it doesn't trip, but the house one does then you've narrowed it down to one of the other two, slightly quicker for you.
  25. ZippyCat

    ZippyCat Member

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    Hi Garry,

    I’ve been struggling to find an external link (much to my annoyance :mad:); at work we have access to a subscription based database which allows us to download PDF’s of each standard (not allowed to pass them on as our company name gets put across the page). BS 1363 is split into several documents of which part 2 is the relevant section for socket outlets etc. Skimming through it I couldn’t see a conclusive line stating the overall rating for a double socket, but it is ambiguously implied.

    When I’m referring to the spur scenario I’m trying to identify that if the load exceeds 13A you need to provide a means of limiting the current regardless of cable size. If a double socket was rated at 26A you would be required to limit the current to 13A, however this is not the case. If a single double socket is ok then why not two singles?

    Also I feel if sockets were rated at 26A they would need to clearly say 2x13A, not 13A or 26A. I’ve had a look around work at some technical sheets which indicate some manufacturers test their sockets to 20A but certainly not 26A; however they are still officially only rated at 13A total.

    I also found this in the past which I did post some time ago in another thread:

    ‘All MK socket-outlets are manufactured to comply with BS1363 part 2: 1995 and are rated at 13A per unit. Double socket-outlets have been manufactured and tested to exceed this rating by margin that allows electrical safety and reduces the risk of heat and mechanical damage to components due to overloading. It should be noted that BS1363 part 2: 1995 does not allow double sockets to operate at twice the permissable maximum loading and it should be remembered that double socket-outlets are not manufactured to be able to withstand a 26A load for sustained periods of time. Research by ourselves and third party organisations has shown that all MK double sockets can safely withstand a continuous load of 19.5A for an indefinite period. Increasing the load slightly will begin to cause heat and mechanical stresses on the components in a relatively shortperiod. Testing showed that a load of 22.3A was sufficientto cause heat stress that would cause a browning of the faceplates and sufficient heat to cause insulation damage to cable cores. A load of 24A for 43 hours was sufficient to cause significant heat damage to the material in which the socket-oulet was situated and within 75 hours sufficient to cause significant damage that would lead to the very real potential of fire.’

    I completely agree with you that this is not clear enough, which is evident by the fact that a large proportion of electricians are completely unaware of such limitations. The only way I could see this being made any clearer in the future would be if it became a problem (unlikely to be a problem as people have been doing this for years). :)
  26. John7

    John7 Member

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    Well, by my "rough" calculations, your total demand for all items would be somewhere between 1.4 and 2.0 kW. That is up to a max of 8.3 amps which is well within safety limits of a double socket outlet.

    If your main breaker is trippping (60 or 100 Amps) and not the ring main (usually rated at about 32Amps) it means that you have an RCCD main breaker and is not tripping through over current, but because of an Earth Leakage problem.

    One of your devices (or a multi-plug adapter) has a power supply problem
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  27. dunks517

    dunks517 Active Member

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    My Anti-virus etc is set to 0200, its a mystery! However one drive will be plugged in tonight and so forth!
    Last edited: Jul 10, 2008
  28. chrish16

    chrish16 Member

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    Hi guys
    I was hoping someone could clarify something for me.
    In my attic i have only 1 double socket. I think this is fed as a spur from the ring main on the floor below, as i cannot see anywhere to accomodate another main on the board. Also the lights in the attic are on teh same circuit as the lights on the floor below.
    If it is a spur how much would i be able to operate from that double socket. I would have an amp, bluray, 2 PCs, fridge, projector or lcd or plasma, network switch, sky box. I'm guessing this will all be ok, it will be all run from a mains conditioner extension. I would need to put some kind of heater up there also. I understand that there is a rule something like a socket has max of 3KW, does this mean if i have a 3KW heater plugged in i would not be able to plug my other electronics in?
    I can take a photo of my board if you like so hopefully you can tell me what is what. If it was required to add a new ring main for the attic does anyone have an idea of the cost?
    Regards
    Last edited: Jul 11, 2008
  29. John7

    John7 Member

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    You would definately need another socket, spurred off the main ring if adding heating. Would probably be better to extend the ring into the loft with all that kit.

    No idea of cost though, would dpend on access to existing ring and route into loft (do walls need chasing/filling/decorating)etc.
  30. Gary Lightfoot

    Gary Lightfoot Active Member

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    Hi Zip,

    I've been doing a fair bit of googling with no luck myself so I know how you feel! I'll have a read up on part two though - thanks for the tip.


    I'm not sure why you'd need to limit the current if the double was rated at 26A - the cable and double s/o would be fine at that current, if not close to the limit (and I've always wondered why spurring is fine if the cable was rated at less than 32A anyway). The regs may say that if you add another socket to the existing spur (making a radial) I can understand the need to limit the current since you can exceed the cables rating, but again, the reasoning is ambiguous with reference to the socket limitations.

    Good point about the singles, though the counter argument could be that if two singles were fitted they could be upgraded to two doubles later on. The regs tend to think of things like that yet are ambiguous over other stuff (or it's there but you really need to delve to find it).

    True, but due to ambiguity, you can see why the 13A rating can be thought to be 13A per socket since you can only plug one 13A plug into each one.

    That's more like it. :)

    True as well. Diversity is the factor here I guess and as you rightly say, until it becomes a problem there's probably no need to spell it out any further.

    Cheers

    Gary

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