Live to Neutral would take out your fuse. You have sockets on a 15a fuse?
What type of supply
- Thread starter scantronic
- Start date
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Yeah downstairs ring main is 15 amp upstairs ring main is 30 amp and alarm is wired into the lighting circuit
The fuse can blow without an earth being present, by shorting live to neutral, so that would not automatically mean an earth is present. But it is highly likely there is an earth at the sockets an you say you have tested these? The lighting circuit would be a different matter though. Back in the day the regulations did not require an earth to be present in the lighting circuit, but know does. If your existing installation dates back to the pre- 1970s, it maybe that you have no earth at the lights, if so you must not have installed class 1 /metallic fittings.
Ok, would I be able to find out if I open up the fuse box?
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Nope.
Is there anything I can do with a multimeter? Or will it be alright it's only the lights
You could test on continuity from the earth clamp on your incoming cable to an earth on the lighting circuit. Whilst this wouldn't prove your earth completely, it would at least tell you it's connected throughout your wiring back to this clamp
And, 'it's only the lights' the metal light switches are probably the accessory you touch the most, so if one of those became live (with no earth) you'd certainly get a surprise!
And, 'it's only the lights' the metal light switches are probably the accessory you touch the most, so if one of those became live (with no earth) you'd certainly get a surprise!
Yeah certainly a shocking surprise, how would I go about checking the continuity do I attach and exta cable to the clamp the have my meter by the light switch? And do I turn off the power for that?
turn the power off, and if the meter cables aren't long enough, but use another cable from the light switch earth to the multimeter (don't try adding anything to the clamp)
Yes, measure the resistance of the extra cable first. You'll need to deduct that from the actual measurement to get the ACTUAL earth continuity figure.
Too bloomin' right you do. Turn it off on the main switch so all of the power is off. We do not know what is going on, so care is essential.
It's probably DIY-speak, so he probably doesn't really understand that question.
You know, common DIY-speak……
sockets are on a ring
light socket = light switch
plug socket = socket
low voltage = 12volts
etc etc
You know, common DIY-speak……
sockets are on a ring
light socket = light switch
plug socket = socket
low voltage = 12volts
etc etc
Earth=cpc
Test=yeap it works
Test=yeap it works
Thanks for all the replies, the downstairs power ring main is 15 amp and I'm going to test the earth tomorrow night so I will update when I have done it, thanks so much for your help I really appreciate it
There are few ways of testing continuity of conductors in a circuit and this should always be performed with the power off.
You can do this with a long lead attached to the earth terminal of earth board and then test at the open end of the lead and earth terminal of accessory through the probes of the meter, if you also do an end to end test on the long lead you can deduct this from the overall reading and that will give the value of your (r2 earth).
You can also test using r1+r2 (line and earth/CPC). At the board you disconnect the line (live/r1) and connect this to the CPC (r2) of that circuit. Then go to each accessory on that circuit and test (with multimeter) between line and CPC, on switched lights, the test should be undertaken with the switch in the closed/on position and test between switch line/live and CPC, this will give you the r1+r2 of circuit and confirm earth continuity. The second test is devised for radial circuits, if testing a ring then end to end continuity of each conductor would be taken, if this satisfactory then the line/live can be loop connected in a figure of 8 to the cpc and test taken at each socket.
https://www.tlc-direct.co.uk/Book/8.4.1.htm
You can do this with a long lead attached to the earth terminal of earth board and then test at the open end of the lead and earth terminal of accessory through the probes of the meter, if you also do an end to end test on the long lead you can deduct this from the overall reading and that will give the value of your (r2 earth).
You can also test using r1+r2 (line and earth/CPC). At the board you disconnect the line (live/r1) and connect this to the CPC (r2) of that circuit. Then go to each accessory on that circuit and test (with multimeter) between line and CPC, on switched lights, the test should be undertaken with the switch in the closed/on position and test between switch line/live and CPC, this will give you the r1+r2 of circuit and confirm earth continuity. The second test is devised for radial circuits, if testing a ring then end to end continuity of each conductor would be taken, if this satisfactory then the line/live can be loop connected in a figure of 8 to the cpc and test taken at each socket.
https://www.tlc-direct.co.uk/Book/8.4.1.htm
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