USB outlets in sockets

[Evans Electric]

Will the increased use of  USB  chargers in sockets  result in conventional megger  testing @ 500V  becoming untenable  due to the cost of disconnecting  and reconnecting . 

Why are they not switched ?  They are permanently connected across L-N  ....how come the socket switch doesn't isolate them ?  

 

[Blue Duck]

Just test em at 1000v, should clear up nicely... :innocent

Okay probably not and to add to the issue there are more & more accessories and fittings with usb ports....

 

[Evans Electric]

Well a sparks I know has fitted  a  house out , virtually , with them  .  If you were testing it would be  disconnecting them all  and refitting  them after L - N tests.  

 

[SirKit Breaker]

Good point, and one that i have not considered even though i teach I&T. The easiest solution i can think of would be to join both of the live (L and N) conductors together and insulation resistance test at the usual 500v between them and the CPC, like you would do for a lighting circuit with ballasts or any other equipment vulnerable to test in the circuit. I would think that these USB sockets would be capable of withstanding the test voltage, but the test results would be way off.

 

[Doc Hudson]

With new circuits, a hand full of Wago's  should allow a quick test on the full cable run @ 500v prior to fitting the USB accessories. But on EICR, or additions to a circuit that already has USB's scattered around I would do 500v L->E, N->E (or L+N->E). Then L->N @ 250v. Unless I've seen manufactures documentation saying their USB sockets can withstand 500v IR testing I would assume they will be damaged and not test at that voltage. I don't think I would start opening up existing USB accessories to isolate them from testing, to then put them back in circuit afterwards, as I think this is more likely to introduce faults that weren't there before.

On a slight tangent, do these USB sockets have any natural earth leakage via their circuitry? e.g. if you had a lot of them all fed from the same RCD could you get nuisance tripping problems.  

Doc H 

 

[kerching]

As an experiment a few months ago .....I was bored, I have issues........I temp connected a couple of elcheapo USB sockets to a ring on a new job ( these were eventually being fitted in my garage )....tested.....powered up....tried loop and RCD test at a few sockets ( yes, I KNOW, but this was a test) .the results were all over the place, even tests at adjacent sockets were miles apart

so, in conclusion, not a clue  :coat

on reflection  I should probably have made a note of my findings  :innocent

just saying 

 

[Murdoch]

I recommend to clients who ask for them, that they keep the plug in type - so they can be switched off or unplugged.

When people realise that they can't be switched off or isolated they seem to have 2nd thoughts.

Back to the testing so using the Wago suggestion above, you would (obviously) need to retest the continuity after the USB sockets are fitted .....................

 

[Sidewinder]

They also, must, be marked as compliant with the latest version of BS1363, as until then, they were not a recognised product.

There are also possibly millions out there that are not compliant with the standard.

Just think of the usual suspects for compliance and non-compliance.

 

[Andy™]

another potential issue if you are testign when the circuit is not finished, if you then squish a conductor whilst screwing the socket back, it wont be noticed since you have already done the IR testing

 

[Sidewinder]

This is why there is a proposal in the 18th DPC such that one can IR test @ 250V on new installs I believe.

 

[rapparee]

I recommend to clients who ask for them, that they keep the plug in type - so they can be switched off or unplugged.

When people realise that they can't be switched off or isolated they seem to have 2nd thoughts.

Back to the testing so using the Wago suggestion above, you would (obviously) need to retest the continuity after the USB sockets are fitted .....................

Funny I talked a work colleague out of this as well only yesterday, he thought they were wonderful, when I told him they were forever "live" and had no protection, he decided to stick with the standard charger.

 

[roys]

Not forever live if you do it the same way I did it

 

[Andy™]

what appliance had its plug & flex nicked to make that?

 

[kerching]

Not forever live if you do it the same way I did it

View attachment 9147

As the late and lamented Prof Heinz Wolfe would have said...."A vewy ewegant sowution to a common pwoblem "

 

[roys]

what appliance had its plug & flex nicked to make that?

Can't quite remember, but it is a habit of mine cutting the leads of kit destined for the bin as they do come in handy, except if they are double insulated of course.

 

[Ardet R]

I think the BG USB sockets state that they can be IR tested and guarantee a reading >10MΩ.

Most USBs now ought to be (but probably aren't) only live when a USB plug is inserted, they certainly were talking about that as a basic approach.

 

[Evans Electric]

if you then squish a conductor

Is this new terminology  coming in with the 18th ed.  ?   

Nothing in the 17th about "Squished conductors"     :C

 

[Andy™]

Is this new terminology  coming in with the 18th ed.  ?   

Nothing in the 17th about "Squished conductors"     :C

its not in 18th, but they are planning on putting that in 19th due out next july

 

[Evans Electric]

Oh !!   I thought the 19th would be much sooner than that !!!   

A whole year with only one new edition of the Regs  Wow!!!

 

[Andy™]

no, you have 3 amendments too