Volt Drop

[hitchin72]

Good Morning

Visited a property yesterday. Customer saying only certain appliances working from double socket in bedroom. Electric toothbrush yes, vacuum cleaner no.

After inspecting socket and wiring find that the socket has been taken as a spur from downstairs lighting circuit on 6A MCB. Circuit tests indicate the circuit itself is okay. Double socket removed and blank plate fitted.

I am thinking that volt drop is the reason the vacuum cleaner did not work but lower power devices still did. Is this correct?

Many thanks in advance

 

[Meggerman]

If you put a 3A fuse in to a 3KW (13A) Kettle plugtop and turned it on, what outcome would you expect?

 

[Pete999]

Sorry I may have miss read your thread, the socket has been spurred from a lighting circuit so you have removed the socket and blanked it off, and you say the circuit's OK, you need to remove the leg feeding the socket in it's entirety for the circuit to be OK.

 

[Meggerman]

Sorry I may have miss read your thread, the socket has been spurred from a lighting circuit so you have removed the socket and blanked it off, and you say the circuit's OK, you need to remove the leg feeding the socket in it's entirety for the circuit to be OK.

Does he need to remove wiring? Someone could install a 5A socket in future for a lamp.

 

[Richard Burns]

If the circuit was all OK and correctly wired then you would probably find that you could do the vacuuming from that socket (whilst pushing the limits of the MCB).
The likely explanation for a the results you found could indeed be volt drop but only because there was a high resistance joint /loose connection somewhere in the circuit, then when a higher current was drawn the resistance would drop a greater proportion of the voltage and prevent a motor from working. Alternatively a loose connection may allow a low current but spark away the slight contact when drawing a higher current.

 

[Hawkmoon]

Good Morning

Visited a property yesterday. Customer saying only certain appliances working from double socket in bedroom. Electric toothbrush yes, vacuum cleaner no.

After inspecting socket and wiring find that the socket has been taken as a spur from downstairs lighting circuit on 6A MCB. Circuit tests indicate the circuit itself is okay. Double socket removed and blank plate fitted.

I am thinking that volt drop is the reason the vacuum cleaner did not work but lower power devices still did. Is this correct?

Many thanks in advance

No, not volt drop but possibly an extremely loose connection perhaps? Assuming the vacuum cleaner etc does not trip the 6A MCB.


Edit: Ignore - RB posted while I was typing

 

[Meggerman]

This is now being overanalysed. A Henry Hoover will trip a 6A MCB with the inrush current when it starts. Try running one of a pendant

 

[Pete999]

Does he need to remove wiring? Someone could install a 5A socket in future for a lamp.

Well I don't know about you Meggerman, but the chances of that happening are, IMHO pretty slim, better be safe than sorry, remove the wiring.

 

[uksparks]

I wired a radial in upstairs in my house, didnt have any 20A to hand so stuck a 6A on it temporarily, the mrs then plugged the hoover in and it tripped it, more than likely overloaded it, as I would imagine most hoovers probably draw 10A+ possibly.

 

[uksparks]

Pete999, you didn't happen to work for a nursing home doing maintenance did you? Off topic I know, but a stab in the dark here..

 

[Pete999]

Pete999, you didn't happen to work for a nursing home doing maintenance did you? Off topic I know, but a stab in the dark here..

No why?

 

[uksparks]

Someone my parents know in northampton with approx your qualifications and called Pete, must be another Pete. I'm a northampton person myself, well lived there for 28 years them moved to leicester with the mrs as she had a house etc.

 

[Pete999]

Someone my parents know in northampton with approx your qualifications and called Pete, must be another Pete. I'm a northampton person myself, well lived there for 28 years them moved to leicester with the mrs as she had a house etc.

Whereabouts do you live?

 

[Pete999]

Whereabouts do you live?

Sorry Leicester, didn't see that bit, no mate I work for HMG

 

[hitchin72]

If you put a 3A fuse in to a 3KW (13A) Kettle plugtop and turned it on, what outcome would you expect?

Meggerman
Thank you for the reply. The MCB did not operate so did not think an overload was the issue. Householder asked me the question and volt drop was my first thought.

 

[hitchin72]

Pete999
Thank you for replying. I should have said the results of the circuit tests were okay not the circuit itself. I put a terminal block on the legs and wired the cpc to the metal backbox. I put a blanking plate over the backbox and explained to the householder why/what I had done as a temporary fix. I need to follow up today/tomorrow.

 

[hitchin72]

Richard
Thank you for your comments.

 

[hitchin72]

Thank you to all
Sorry about the disjointed replies of thanks. Not quite up to speed with the correct way of replying to individuals. Still learning. Much appreciated.

 

[uksparks]

Whereabouts do you live?

I lived in Brixworth until 28, parents still live there so keep getting roped into doing jobs there for them and neighbours etc, I live just near J21 of the M1 now on the edge of Leicester.

 

[Pete999]

Good Butcher in Brixworth we go there quite a lot for decent steaks.