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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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How Can This Happen (Electrical)?
In one bedroom we have a ceiling fan supplied from the lighting circuit.
It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. -- bert |
#2
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How Can This Happen (Electrical)?
On 28/02/2019 12:21, bert wrote:
In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Possibly a suppressor in the motor has failed and the resulting inductive spike is coupling into an adjacent circuit. Makes sense as you say it doesn't always happen, probably only when the voltage happens to be on a high part of the AC cycle. Cheers -- Clive |
#4
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How Can This Happen (Electrical)?
In article , Clive Arthur
writes On 28/02/2019 12:21, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Possibly a suppressor in the motor has failed and the resulting inductive spike is coupling into an adjacent circuit. Makes sense as you say it doesn't always happen, probably only when the voltage happens to be on a high part of the AC cycle. Cheers Now that is a possibility. Would explain why it has just started to happen. -- bert |
#5
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How Can This Happen (Electrical)?
On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote:
In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? -- Regards, Paul Herber http://www.paulherber.co.uk/ |
#6
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How Can This Happen (Electrical)?
On 28/02/2019 14:15, Paul Herber wrote:
On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? Probably not, RCDs don't just detect earth leakage but any current imbalance between live and neutral. It wouldn't actually matter where it was earthed if there was leakage to earth and it wouldn't affect other circuit unless they also had an earth leakage problem as RCDs aren't connect to earth. |
#7
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How Can This Happen (Electrical)?
On 28/02/2019 14:38, dennis@home wrote:
On 28/02/2019 14:15, Paul Herber wrote: On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? Probably not, RCDs don't just detect earth leakage but any current imbalance between live and neutral. It wouldn't actually matter where it was earthed if there was leakage to earth and it wouldn't affect other circuit unless they also had an earth leakage problem as RCDs aren't connect to earth. Quite agree. I think Clive is probably right as to the cause. Within the consumer unit, all the lives and all the neutrals are connected together, so there's scope for some coupling between circuits. The only thing that's really surprising (to me) is that the RCD protecting the lighting circuit does not trip. (I may be making a fool of myself here. Hope not!) |
#8
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How Can This Happen (Electrical)?
On 28/02/2019 15:00, GB wrote:
On 28/02/2019 14:38, dennis@home wrote: On 28/02/2019 14:15, Paul Herber wrote: On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? Probably not, RCDs don't just detect earth leakage but any current imbalance between live and neutral. It wouldn't actually matter where it was earthed if there was leakage to earth and it wouldn't affect other circuit unless they also had an earth leakage problem as RCDs aren't connect to earth. Quite agree. I think Clive is probably right as to the cause. Within the consumer unit, all the lives and all the neutrals are connected together, so there's scope for some coupling between circuits. The only thing that's really surprising (to me) is that the RCD protecting the lighting circuit does not trip. I wouldn't assume there there is an RCD protecting the lighting circuit. Very many homes don't have them. (I may be making a fool of myself here. Hope not!) -- Robin reply-to address is (intended to be) valid |
#9
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How Can This Happen (Electrical)?
On 28/02/2019 16:44, Robin wrote:
On 28/02/2019 15:00, GB wrote: On 28/02/2019 14:38, dennis@home wrote: On 28/02/2019 14:15, Paul Herber wrote: On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? Probably not, RCDs don't just detect earth leakage but any current imbalance between live and neutral. It wouldn't actually matter where it was earthed if there was leakage to earth and it wouldn't affect other circuit unless they also had an earth leakage problem as RCDs aren't connect to earth. Quite agree. I think Clive is probably right as to the cause. Within the consumer unit, all the lives and all the neutrals are connected together, so there's scope for some coupling between circuits. The only thing that's really surprising (to me) is that the RCD protecting the lighting circuit does not trip. I wouldn't assume there there is an RCD protecting the lighting circuit. Â*Very many homes don't have them. Of course the 18th edition has altered that for future installs (I think you are correct about the OPs lights) Just for info and not related to the OPs question. Domestic properties are now required to have RCD protection on the lighting circuits even if the cables are run in a manner or of the type that would not require RCD protection (eg in trunking or SWA) -- Adam |
#10
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How Can This Happen (Electrical)?
In article , GB
writes On 28/02/2019 14:38, dennis@home wrote: On 28/02/2019 14:15, Paul Herber wrote: On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? Probably not, RCDs don't just detect earth leakage but any current imbalance between live and neutral. It wouldn't actually matter where it was earthed if there was leakage to earth and it wouldn't affect other circuit unless they also had an earth leakage problem as RCDs aren't connect to earth. Quite agree. I think Clive is probably right as to the cause. Within the consumer unit, all the lives and all the neutrals are connected together, so there's scope for some coupling between circuits. The only thing that's really surprising (to me) is that the RCD protecting the lighting circuit does not trip. There's no rcd on the lighting circuits. (I may be making a fool of myself here. Hope not!) -- bert |
#11
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How Can This Happen (Electrical)?
In article
, Paul Herber writes On Thu, 28 Feb 2019 12:21:12 +0000, bert wrote: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. Earthed via a the ring-main circuit? Are you suggesting that the qualified certified to whatever professional electrician who did this has screwed up? Well actually his dozy apprentice did most of the actual work 'til he fired him so yes quite possible. -- bert |
#12
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How Can This Happen (Electrical)?
On Thursday, 28 February 2019 12:26:10 UTC, bert wrote:
In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. -- bert Neutral-Earth faults can trip the RCD. |
#13
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How Can This Happen (Electrical)?
Where is the switch for the fan, in the fan/light itself?
I'd start there. Brian -- ----- -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "bert" wrote in message ... In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems. In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on. Puzzled as to how this can happen - and where to start looking. -- bert |
#14
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How Can This Happen (Electrical)?
One on the fan unit and one at the wall. I've checked the wall switch
and tightened up the neutral connection by a turn or two. I've "instructed" (AKA pleaded with) swmbo to only use that switch for the time being. For reason best known to himself the electrician wired the extension circuits live to the switches whereas the rest of the house is wired live to the ceiling rose. In article , Brian Gaff writes Where is the switch for the fan, in the fan/light itself? I'd start there. Brian -- bert |
#15
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How Can This Happen (Electrical)?
"Tim+" wrote in message
... bert Wrote in message: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems.In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on.Puzzled as to how this can happen - and where to start looking.-- bert It would suggest that it's not supplied by the lighting circuit... Are you sure that your RCD *only* protects the ring mains and not *all* circuits such as cooker, lighting in addition to ring mains? My understanding is that an RCD in the "fuse box" is usually upstream of the ring main MCBs (over-current sensors, equivalent to wire fuses) and protects the whole house. Our previous house had two RCDs: one was a separate unit that was between the meter and the fuse box, and the other was within the fuse box. Even if the RCD within the fuse box was tripped, all power went off, including to non-ring-main circuits such as lighting and cooker. What happens if you manually turn off the RCD? Does the lighting still continue working? |
#16
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How Can This Happen (Electrical)?
"Tim+" wrote in message ... bert Wrote in message: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems.In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on.Puzzled as to how this can happen - and where to start looking.-- bert It would suggest that it's not supplied by the lighting circuit... Doesn't explain why it can be switched on again when the RCD trips. |
#17
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How Can This Happen (Electrical)?
I was thinking of back EMF.
That could make it back through the lights to the other circuits as a spike of some kind. Brian -- ----- -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "Tim+" wrote in message ... bert Wrote in message: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems.In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on.Puzzled as to how this can happen - and where to start looking.-- bert It would suggest that it's not supplied by the lighting circuit... Tim -- Please don't feed the trolls |
#18
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How Can This Happen (Electrical)?
On 28/02/2019 18:27, Brian Gaff wrote:
I was thinking of back EMF. That could make it back through the lights to the other circuits as a spike of some kind. Brian |
#19
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How Can This Happen (Electrical)?
In article , Tim+
writes bert Wrote in message: In one bedroom we have a ceiling fan supplied from the lighting circuit. It's been there for over 10 years no problems.In the past few nights a couple of times when switching it off the RCD protecting the ring mains has tripped. But the lighting circuits don't go through it and the lights are still on including the one which is part of the fan and the fan itself can be switched back on.Puzzled as to how this can happen - and where to start looking.-- bert It would suggest that it's not supplied by the lighting circuit... Tim But its definitely not supplied by any circuit protected by the RCD. -- bert |
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