Not incorrect advice. (except by you).
Do they have a physical switch in them? If not, they must consume electricity.
USB Plug Sockets
- Thread starter Tsmedley
- Start date
Not incorrect advice. (except by you).
Do they have a physical switch in them? If not, they must consume electricity.
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MK documentation seems silent on the matter, but other manufacturers have something to say on the matter. For example, for BG ones (click here) it says:
Unless I'm misunderstanding, I can but presume that they mean 0.4 MΩ (rather than 0.4 mΩ
. If that is what they mean, although the USB stuff apparently won't come to any harm, it would render IR testing of the circuit pretty useless!Kind Regards, John
Thanks John!
I'll put in an info request to MK and will post any response.
Given the 0.4MΩ feature, it looks like its best to WAGO the connections in the box, do IR, etc and then fit the socket before live testing….
I'll put in an info request to MK and will post any response.
Given the 0.4MΩ feature, it looks like its best to WAGO the connections in the box, do IR, etc and then fit the socket before live testing….
To add more to this the spec of BG ones linked to by JohnW2 clearly state:
Stand-by Power <50mW.
Which is clearly not "no power".
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You're welcome. If that 0.4MΩ means what it appears to say (with an apparent typo!), what you suggest would seem necessary when initially fitting the socket but, unfortunately, the same process (moving connections from socket to Wagos, or whatever, and then back again after testing) would presumably have to be repeated every time someone wanted to do an IR test on the circuit. With these devices presumably likely to become increasingly common in the future (and, quite probably, several per house), IR testing may well become a rather time-consuming exercise!
Kind Regards, John
Yes, you are very clever. ... and, by my calculation, 50mW continuous should cost about 7p per year, so I can see that it may really be very important to you.
Kind Regards, John
I've certainly seen it mentioned, but I thought only for situations in which it was 'impossible' ('impracticable'??) to disconnect the equipment (which clearly isn't the case with what we're discussing). If such a test gives OK results, it obviously rules out any L-E or N-E problem, but it leaves the possibility of a L-N problem.
It's certainly 'better than nothing' and if (as will usually be the case) we're talking about T+E cables, the layout of such cables is such that it must be incredibly unlikley that there would be an L-N IR problem within the cable without a (L+N)-E one. However, isolated L-N problems can arise within connected accessories etc. (or in any flex), even if such is very unlikely within T+E cable.
Kind Regards, John
On the other hand disconnecting equipment before testing raises the risk of damage during disconnection and means that the disconnected equipment doesn't get tested.
The PAT world only does P+N-E testing despite that fact that flex is far more common there than in fixed installation.
Having said that I do question the wisdom of these USB sockets. The power consumption when non-faulty and not in use may be negligable or in the case of a design with a mechanical switch mechanism zero but having a load of unused power supplies permanently connected doesn't seem like the greatest idea. Yes the risk of one overheating and catching fire should be very small but it still doesn't seem wise to multiply it unnessacerally.
Also it's not really relavent for the home because noone bothers with in-service testing there anyway but these things seem likely to fall through the cracks in many test regimes. They won't get PAT tested because they aren't portable and they are unlikely to get adequate testing as part of installation testing either (I could be wrong but I expect they have floating outputs meaning an input-output IR test would be appropriate).
The PAT world only does P+N-E testing despite that fact that flex is far more common there than in fixed installation.
Having said that I do question the wisdom of these USB sockets. The power consumption when non-faulty and not in use may be negligable or in the case of a design with a mechanical switch mechanism zero but having a load of unused power supplies permanently connected doesn't seem like the greatest idea. Yes the risk of one overheating and catching fire should be very small but it still doesn't seem wise to multiply it unnessacerally.
Also it's not really relavent for the home because noone bothers with in-service testing there anyway but these things seem likely to fall through the cracks in many test regimes. They won't get PAT tested because they aren't portable and they are unlikely to get adequate testing as part of installation testing either (I could be wrong but I expect they have floating outputs meaning an input-output IR test would be appropriate).
Unless you know better, MK do not seem to make a combo 13A socket + USB charger, but they do have the MK5837, which is a USB charger module.
Two points from the spec: https://www.tlc-direct.co.uk/Technical/DataSheets/MK/MKK5837_Info.pdf
1. There is SELV isolation between mains input and USB output @plugwash
2. The module is disconnected from the supply (single pole isolation) when the USB shutters are closed (they quote 1.5KV isolation). So no need to disconnect this item during IR tests.
Two points from the spec: https://www.tlc-direct.co.uk/Technical/DataSheets/MK/MKK5837_Info.pdf
1. There is SELV isolation between mains input and USB output @plugwash
2. The module is disconnected from the supply (single pole isolation) when the USB shutters are closed (they quote 1.5KV isolation). So no need to disconnect this item during IR tests.
All true.
I'm inclined to agree - although it seems to be an unavoidable fact of life that we are seeing increasing numbers of low-power SMPSs powered-up 24/7. I suspect that it is space issues that have precluded manual switches for the USB supply - and to try to implement a 230V switch actuated by inserting a USB plug would probably introduce all sorts of potential problems. If they made dedicated USB accessories, rather than trying to fit all this stuff in along with 13A sockets+switches, there would probably be enough space for manual switches for the USB supply.
Indeed - if you look at page 5 of this ESC 'Safety Screeing Report', you'll see that they did input-output IR testing.
Kind Regards, John
Interesting. That sounds along the lines of what I suggested ...
Kind Regards, John
Acording to their home page they have just introduced them.
http://www.mkelectric.com/en-gb/Pages/USB.aspx
Unlike with the USB charging module however I can't seem to find any real data on them. No information on whether the outputs are earth referenced or floating, no information on whether the power supply is continuously connected or switched (the sockets do not appear to have the shutters that the charging module has, so I would guess continually powered).
Thanks plugwash.
I've asked MK the question and will let you know when/if I get response.
I've asked MK the question and will let you know when/if I get response.
For an individual it is insignificant, but multiply that by tens of thousands that could soon be in use and it becomes significant.
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