RCD nearly tripping with laser printer

[manville]

Hi,
just got a new laser printer and it has been tripping the RCD (so due to go back for an exchange in case we just got a duff one) - but only when an elderly laptop is plugged into the same circuit and then the printer wakes from sleep mode. Standard 30ma RCD at the Consumer unit should be able to tolerate this sort of insult. When I don't have the laptop (or anything else) plugged into that circuit and I wake the printer up I still get an audible "click" at the consumer unit although it doesn't trip out. (suggesting the RCD is registering an earth leakage just insufficient to fully break the contact)

If the new printer behaves exactly the same way should I be worried enough to get an electrician to check the house for leakage / dodgy wiring given my background reading suggests there may be an excess earth leakage that is bringing the residual current near to its threshold?

The complicating factor is this is a rental property and I probably need good evidence to get the landlord to fork out for the sparky.

 

[plugwash]

What does the RCD in question supply?

 

[manville]

What does the RCD in question supply?

Upstairs plug sockets. (Here's a picture of the RCD)

Untitled

• manville
• 9 May 2012
• 1

 

[plugwash]

In that picture I see one RCD (the double width device on the left) and two MCBs. Presumablly the RCD is suppllying the MCBs.

Can you be explicit about what device is tripping and what each device covers.

Sorry if you already know all this but a lot of beginners get RCDs and MCBs confused and we need to be clear on exactly what the problem is before we give advice for solving it.

 

[manville]

From the photo the right hand switch is the one that is tripping and needing to be reset.

I've just googled the part number - it appears to be a 6A MCB (if I've got that right) so apologies for my ignorance. It seems ludicrously small for a ring main (albeit upstairs in a small house) and might explain why even a vacuum cleaner tripped it on occasion.

 

[rebuke]

If it's actually a ring main then yes a 6A MCB sounds mad - perhaps there was a 32A one fitted and it failed, and someone only had a 6A spare that they swapped in 'temporarily'. Laser printers do tend to draw a fair amount of current at times, so I would suspect your printer itself is absolutely fine.

I'd suggest getting in an electrician to check whats going on with that circuit - if the cable is sufficiently sized then it might be possible to just put in a bigger MCB (note do *not* do this unless you are able to confirm the cables are big enough, otherwise it could be very dangerous indeed).

 

[manville]

Given I'm only a tennant are there any specific requirements for a minimum spec. on domestic plug sockets that I can quote to make sure it's the landlords problem or do I need to go into careful negotiation mode?

It's an early 90s (??late 80s) built house so the wiring should be to reasonable spec by the standards of the day.

 

[dannyboi2003]

6A mcb for sockets is stupid but there may well be a reason we cant see, best to get in touch with your landlord and say your having problems with the upstairs sockets and can they arrange for an electician to visit, may just be a case of changing the mcb for a 32A one but the circuit will need to be tested/inspected first. Out of interest what goes off if you switch off the 32A mcb on the left, downstairs sockets im guessing? Any chance you can post a pic of the full consumer unit showing all mcb's?

 

[securespark]

Run away...................

 

[securespark]

Sorry.


It's just whenever I see something like that I begin to smell an exceedingly large rodent...

 

[ntb]

Can you post a photo that shows all of the consumer unit circuits?

 

[Steve]

Laser printers do draw a lot of current. We had new computers fitted at work in one shop, and they accidentally plugged the laser printer into a protected socket. It overloaded the UPS - it was flashing an overload, normal current being about 4-5 amps (3 tills and a PC).

 

[manville]

Here's the other half of the CU:

Untitled

• manville
• 10 May 2012
• 1

With the Kitchen spurs and the cooker also on 32A MCBs did the installer just run out of Amps? If so I calculate 120A worth of MCBs in the CU.

Now got the printer running fine off a downstairs socket (rather untidy use of an extension lead though).

Need to rename this thread really: "MCB overloaded by Laser printer" - or "Check your power supply before buying new equipment"

 

[ntb]

Not as bad as I feared. I was worried that someone had been dumb enough to wire sockets into a lighting circuit but it is most probably just an inappropriate mcb on that power circuit. Definitely needs checking and sorting by a proper spark though - I can't imagine that any self respecting electrician would leave a 6 amp mcb on a power circuit which makes the whole installation suspect in my mind.

 

[ban-all-sheds]

"Kitchen Spurs" not on the RCD?