I need some help please, my house CB trips unless I remove one of the 30A fuses in my old Wylex Bakelite fuse box. There are 8 fused circuits altogether. The one I removed feeds 1/2 the house's wall sockets(about 15 in all), an electrician quoted £200 for new CU, £200 fitting and fault detection anything up to 5 days! I think I can fit a CU, however tracing the short isnt easy. Done the obvious (removing all appliances) I have an ammeter which can test up to 400v but prefer to just "bell test" dead cabling with it to avoid dying horribly, besides the circuit wont stay up anyway! Is there a socket tester which will either detect shorts or at least determine whether main wiring is ring or other type? Also if I buy a CU to replace old fuse board, do they all come with RCD or is that extra?
circuit breaker tripping
- Thread starter brightspark13
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since you do not know what you are doing i would get more quotes for it, and how are you going to test it?
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Why do you call yourself "brightspark13"
That username gives me the impression that you are a sparky (and a clever one at that).
The work you describe should be well within the capability of a bright sparky.
The fact that you are asking how to do this speaks volumes.
Your limited knowledge of testing and lack of test tools is also significant.
That username gives me the impression that you are a sparky (and a clever one at that).
The work you describe should be well within the capability of a bright sparky.
The fact that you are asking how to do this speaks volumes.
Your limited knowledge of testing and lack of test tools is also significant.
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Well thanks guys..... The Brightspark nickname goes back 20 years because I have a Master of Science degree - but in computing - not electrics! I know its a multimeter not an ammeter and a ring or radial circuit. If I asked you the difference between a stateful inspection or a proxy firewall , you wouldnt be so smug!
I am sorry but I have to back SwindonSpark on this one, this fellow is obviously a novice with little / no electrical training or experience and has no proper test equipment (bar a 400v ammeter??). This makes me feel uneasy of even starting to explain how to faultfind this circuit.
But would I put my life on the line for it?brightspark13 said:
No, but he wouldn't die/kill someone else/burn the house down/break the law if he got it wrong.brightspark13 said:
Why would anyone ask LAN/WAN questions on a DIY electrics forum anyway? BTW can you explain what a stateful inspection or a proxy firewall is. I would be interested to know. I would assume a proxy firewall to be at the server protecting the nodes.
brightspark13 said:
in case anyones wondering.
statefull inspection is where the firewall keeps state between packets to track connections. iirc the linux kernel reffers to this as connection tracking (and if you are really interested you can view the state through /proc/net/ip_contrack) statefull inspection allows you to control flow at the connection level i.e you can let people connect out but not connect in. Theese tables are also used to track connections for 1 to many nat.
a proxy is a tool that sits at the application level and re-makes the requests on behalf of the client.
There is also the possibility of a simple TCP proxy which re-makes the TCP connections but doesn't touch anything flowing inside.
Has anyone got anything helpful to say - or not??
the fault could lie in either the wiring itself or if you're lucky, in the connections (if you're luckier, the only connections will be the sockets, which you could then examine easily). check all connections in sockets yourself, check the state of the wires..
take the fuse out and determine exactly what goes off in the house. don't assume anything, check every single socket, light, fixed appliance etc.. now you know what it feeds and where the wiring goes.
to check if its not a radial (ie maybe a standard ring), disconnect all the wiring from one socket (make a break in the wiring), and check what sockets are working and what's not with a low load plug in appliance, ie plug in lamp. if some of the sockets don't work, its a radial. you may have to try this with one other socket, incase you've chosen the last socket on a radial. you could also check the CU to see if two cables leave the fuse, although this won't confirm for definite whether it's a ring.
you will have to be very systematic and logical in your approach, making disconnections where necessary to isolate parts of the circuit. you should be definitely aiming to identify the circuit layout (ie radial, ring, or dodgy interconnected ring etc..).
every situation is different, and you must approach yours uniquely with some of the ideas ive said above. the quickest easiest and most reliable way for you to tackle this would be to directly examine the cables and the routes under floorboards.
oh and a multimeter would come in useful
take the fuse out and determine exactly what goes off in the house. don't assume anything, check every single socket, light, fixed appliance etc.. now you know what it feeds and where the wiring goes.
to check if its not a radial (ie maybe a standard ring), disconnect all the wiring from one socket (make a break in the wiring), and check what sockets are working and what's not with a low load plug in appliance, ie plug in lamp. if some of the sockets don't work, its a radial. you may have to try this with one other socket, incase you've chosen the last socket on a radial. you could also check the CU to see if two cables leave the fuse, although this won't confirm for definite whether it's a ring.
you will have to be very systematic and logical in your approach, making disconnections where necessary to isolate parts of the circuit. you should be definitely aiming to identify the circuit layout (ie radial, ring, or dodgy interconnected ring etc..).
every situation is different, and you must approach yours uniquely with some of the ideas ive said above. the quickest easiest and most reliable way for you to tackle this would be to directly examine the cables and the routes under floorboards.
oh and a multimeter would come in useful
For this job a multimeter will be essential.
With the circuit dead, open up all the sockets and accesories it feeds, and deduuce the order of the daisy chain - this is the 5 days of test and measure to isolate fault.
Also check is the wiring crumbling rubber - in which case it will need replacement, or PVC, and is it in good condition?
Look for arcing/burning that indicate poor contacts. Identify the cable routes. Even if you can't fix it, being able to say here is a wiring map, and the fault is between socket 15 and socket 19 or something will save time and money if you do need to call in assitance.
Your mention of a house 'CB' sounds like RCD or ELCB as incomer, can you read the writing on it and tel us, as it affects if we are loking for an L_N fault or a few mA of L-e leakage. If the latter it could be damp, or a badly placed spider in a junction box.
Are you fed from TT, TN_S or TNC-s - this too affects the answers.
Also check is the wiring crumbling rubber - in which case it will need replacement, or PVC, and is it in good condition?
Look for arcing/burning that indicate poor contacts. Identify the cable routes. Even if you can't fix it, being able to say here is a wiring map, and the fault is between socket 15 and socket 19 or something will save time and money if you do need to call in assitance.
Your mention of a house 'CB' sounds like RCD or ELCB as incomer, can you read the writing on it and tel us, as it affects if we are loking for an L_N fault or a few mA of L-e leakage. If the latter it could be damp, or a badly placed spider in a junction box.
Are you fed from TT, TN_S or TNC-s - this too affects the answers.
Thanks for this....I'll try examining the sockets first. In answer to some of the other questions:
I dont have a CU with MCBs - just an old bakelite fuse board.
The CB I refer to is a large bakelite on/off switch which sits between the meter and the fuse board. It has a reset button and is what trips with the offending circuit fuse in place.
Oh and I do have a multimeter, its not much use as the circuit wont stay up to test live wires! I have assumed that all dead sockets belong to the one ring main and there are no others in the ring which might still be working - so thats something to check.
Thanks again
I dont have a CU with MCBs - just an old bakelite fuse board.
The CB I refer to is a large bakelite on/off switch which sits between the meter and the fuse board. It has a reset button and is what trips with the offending circuit fuse in place.
Oh and I do have a multimeter, its not much use as the circuit wont stay up to test live wires! I have assumed that all dead sockets belong to the one ring main and there are no others in the ring which might still be working - so thats something to check.
Thanks again
BTW - if you do get as far as replacing the CU, you will also need an Insulation Resistance tester, a low-range Ohmmeter, an RCD tester and a Loop tester....brightspark13 said:
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