USB Plug Sockets

[Taylortwocities]

I asked MK

I have a query re the newly introduced combo sockets & USB charger (K2743WHI etc)

I note that your stand alone USB charger unit MK5837 can be left connected during circuit insulation testing as the USB shutter switches off the mains supply to the USB module.
What is the situation with the new combination socket, this does not have shutters on the USB module.

Will the module survive a 500VDC insulation test and, will it be identified as a L-N fault during IR testing?


and they responded

Thank you for your recent e-mail regarding your MK products.

We confirm that our USB socket outlets must be taken out of circuit prior
to insulation resistance testing.

For any further clarification please call our help line on 01268 563720 and
one of our engineers would be happy to assist further with your query.

So that's a real faff, and something to remember when doing EICRs!
Maybe they should supply IR warning stickers to go on to the CU …..

 

[dhutch]

For an individual it is insignificant, but multiply that by tens of thousands that could soon be in use and it becomes significant.

Indeed, personally, I think its crap that they do not have a hard switch to isolate them.

I will be the first to admit that I leave my phone charger plugged in and turn on 24/7 while in the house. However, it gets isolated if I am away for the week, and similarly the charger I keep in the spare room at my parents is only turned on when I am there.

Imagine if every house, hotel, holiday cottage, had 2-3 of these one per bedroom.

No where near as bad as the atrocious freeview boxes, but at least you could switch them off.


Daniel

 

[JohnW2]

... We confirm that our USB socket outlets must be taken out of circuit prior to insulation resistance testing.
So that's a real faff, and something to remember when doing EICRs! Maybe they should supply IR warning stickers to go on to the CU …..

Indeed so ... and those who remind DIYers about all the dead tests they should do after installing a new accessory need to remember to tell people that any IR tests should be performed before, and should not be performed after, installing one of these sockets!

Kind Regards, John

 

[RF Lighting]

There are people here who possess all of these:

1) Socket(s) with USB charging outlets.

2) The equipment to measure currents down in the mA range.

3) The skills to temporarily dismount a socket and put it on a spur in series with such equipment without giving themselves an electric shock.

4) The nous not to plug a fan heater into the BS 1363 outlet when the ammeter is set to a mA range.

Maybe they could do a little test for us?

Had a little go at this today.

I used a new BG branded socket as sold by screwfix.

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• RF Lighting
• 2 Jun 2015
• 1

This is my test setup showing the connections.

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• RF Lighting
• 2 Jun 2015
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With the socket powered up, I had to set my meter to μA to get an accurate reading.

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• RF Lighting
• 2 Jun 2015
• 1

With a phone connected reading in mA

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• RF Lighting
• 2 Jun 2015
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[JohnW2]

With the socket powered up, I had to set my meter to μA to get an accurate reading.

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• RF Lighting
• 2 Jun 2015
• 1

That looks like about 73mW to me.

Kind Regards, John

 

[winston1]

With the socket powered up, I had to set my meter to μA to get an accurate reading.

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• RF Lighting
• 2 Jun 2015
• 1

That looks like about 73mW to me.

Kind Regards, John

Yes, if the PF was unity which I doubt. I however it was, say 0.5, that would give less than 50mW quoted earlier.

 

[JohnW2]

That looks like about 73mW to me.

Yes, if the PF was unity which I doubt. I however it was, say 0.5, that would give less than 50mW quoted earlier.

Indeed - in the absence of a measurement, we can but speculate about the PF. I'm not sure that I would have expected it to be as low as 0.5, though.

Kind Regards, John

 

[plugwash]

I wouldn't be entirely surprised if the no-load power factor was very low, when you get to currents that low things like EMI suppression caps can become a significant part of the total.

Unfortunately I doubt many people here have the kit needed to safely measure power factor at sub-milliamp levels on a mains system.

 

[JohnW2]

I wouldn't be entirely surprised if the no-load power factor was very low, when you get to currents that low things like EMI suppression caps can become a significant part of the total.

Yes, on reflection, I suppose that's very true. Indeed, the suppression caps might even represent the majority of total quiescent 'load'.

Unfortunately I doubt many people here have the kit needed to safely measure power factor at sub-milliamp levels on a mains system.

I imagine that's true. If one had a suitable voltage source at a frequency appreciably different from 50Hz, I suppose one could get a feel for what was going on!

Kind Regards, John

 

[flameport]

So that's a real faff, and something to remember when doing EICRs!
Maybe they should supply IR warning stickers to go on to the CU …..

What they should do is arrange these devices so that the mains power to the USB module is supplied via the switch for the 13A socket.

Insulation testing can then be done with the switches off, avoiding false defects.
End users can switch the things off in the same way as any other socket outlet.

This avoids the need for shutters controlling a mains switch, and would require no additional cost when manufacturing the devices. The only difference internally is where the mains side of the USB module is connected.

 

[kai]

Simple way round the problem, install one as a Fused Spur fed from a DP Switched Fuse-Connection-Unit with neon indicator - just flick off the FCU whenever you are not charging anything, or just before an meggering test.

 

[333rocky333]

The new 2 outlet deta ones have a 2.4 amp tablet port and a 1 amp phone port

 

[oceansoul]

Is having 3 switches not the best way forward for these devices. One for either socket as per normal, then a separate one for the PSU for the USB outlets.

Like this i made in paint.

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• oceansoul
• 7 Jun 2015
• 1

 

[Iggifer]

I'm less concerned about the 50mW wastage than the risk of fire - which is why I've been waiting for MK or Hager to start making them - and not rushed out to buy the chinese tat thats been around for a while

 

[JohnW2]

Is having 3 switches not the best way forward for these devices. One for either socket as per normal, then a separate one for the PSU for the USB outlets. ... Like this i made in paint.

It's a fairly obvious solution, so I wonder if there is a problem fitting three switches in? Also, if it could be done, I suspect that it would be desirable to have a neon for the USB outlets - otherwise I can well imagine that the 'middle switch' would in many cases be left permanently 'on' without anyone noticing - a neon might just prompt some of them to switch it off!

Kind Regards, John