I've been asked to add a USB charging port into a bedroom with a bath in it.
My understanding of BS7671 is that a room with a bath is a bathroom. As such the outlet would be in zone 2 of the bath.
Would I need to power the charger via a safety transformer and could this be built into a +IP4 enclosure similar to a shaver outlet
Thanks for your assistance
Can we clarify the use of Energy Source Classes 1, 2 and 3 for hazard levels of voltages and currents and the standards not discussing SELV, PELV, ELV and LV
If we need the USB socket to be SELV but the usual USB converters don't say they provide SELV - could we achieve the same be creating a simple 12V SELV circuit (using a conventional isolating transformer if needs be), convert to d.c. and then use a 12V powered USB module (of the type usually used in caravans or vehicles - e.g. https://www.12voltplanet.co.uk/cbe-21a-double-usb-charger-grey.html) - I can't see that the module would be able to "un-SELV" the circuit as it were.
- Andy.
I was thinking the SELV source could be to BS EN 61558-2-6 (something like this perhaps, https://uk.rs-online.com/web/p/din-rail-transformers/7720704, or maybe something less RS-priced) - I think that would then satisfy BS 7671's requirements for any specific standards for SELV systems - the remaining parts need only each need to comply with some suitable standard for each individual part. With any installation we're assembling parts complying with a wide variety of different standards - this would just be an extreme example of the same principle. If people don't fancy soldering together diodes, capacitors etc on site, ready built 12V AC to DC converters are available (e.g. https://www.autodoortrader.co.uk/12v-ac-dc-converter-1076-p.asp - but check standard compliance of course)).
- Andy.
What i need to offer is a solution so no soldering or building on site.
I need to consider real world risks to the client and their customer, not just be approved. With what im understanding is that an approved setup could still be fatal in the right situation. Limiting voltage to lower limits I.e 5-12v output, isolated supply and IP rating (marine) USB connector.
Although my first choice will be to discuss installing outside zone 2
Although my first choice will be to discuss installing outside zone 2
I am not sure that helps. As Andy has already mentioned, unless the supply is SELV, no socket-outlet is permitted within 2.5 m. The definition of socket-outlet is very broad and IMHO includes USB - it is not restricted to mains voltage.
the remaining parts need only each need to comply with some suitable standard for each individual part. W
I disagree ... sub-assemblies aren't certified to suitable product standards.
Legislation also gets in the way for that type of 'assembly', including the EMC Regulations 2016.
This definitely falls into what is being covered by Regulation 113.1.
My intention is selv or isolated psu outside this area.
As previously discussed USBs can be selv but this isnt enough for safety purposes whilst charging in a bath.
I'm missing some logic here I think.
Say I take a BS 1363 socket, put it in a BS 4662 back box, add a rubber grommet to BS EN 61340-5-1 and perhaps a choc block or two to BS EN 60998 and hold it into the wall using some screws to whatever standard they're to - is there a standard for that overall "assembly"? (other than BS 7671 itself)
So what's the difference if I take a BS EN 61558-2-6 transformer, and a AC-DC module to whatever standard they're to and connect them together on site?
- Andy.
using some screws to whatever standard they're to
Wood screws used to be to BS 1210:1963.
BS1363 tests use that back box in some tests.
BS61558-2-6 specifies IP rating, and more for the location.
BS61558-2-6 allows other sockets but not linked to the shaver output transformer.
I have a similar problem with a switch ive designed that uses an approved 300vac terminal but it fails compliance when used to 60669.
Sometimes I give up wondering why and just need to interpret the rules.
My USB question is an example of can I? Should I? And that before I get to how do I?
BS61558-2-6 specifies IP rating, and more for the location.
BS61558-2-6 allows other sockets but not linked to the shaver output transformer.
I think some confusion here. We were discussing BS 61558-2-5 shaver sockets (my emphasis). Andy used a BS 61558-2-6 transformer as a component.
BS 61558-2-5: 19.105 Shaver supply units shall be provided with socket-outlets in the output circuit. (emphasis in the original)
My intention is selv or isolated psu outside this area.
As previously discussed USBs can be selv but this isnt enough for safety purposes whilst charging in a bath.
One of the problems, as i see it, is that BS 7671's idea of SELV (especially the extra precautions for within zones in bathrooms) isn't quite the same as other standard's idea of SELV -basically BS 7671 doesn't accept the electronic PSU approach for supplying things within zones and wants a traditional isolating transformer (or the equivalent - say a motor/generator or independent battery) - hence my thought to "front end" the system with a BS EN 61558-2-6 transformer.
- Andy.
My intention is selv or isolated psu outside this area.
As previously discussed USBs can be selv but this isnt enough for safety purposes whilst charging in a bath.
One of the problems, as i see it, is that BS 7671's idea of SELV (especially the extra precautions for within zones in bathrooms) isn't quite the same as other standard's idea of SELV -basically BS 7671 doesn't accept the electronic PSU approach for supplying things within zones and wants a traditional isolating transformer (or the equivalent - say a motor/generator or independent battery) - hence my thought to "front end" the system with a BS EN 61558-2-6 transformer.
- Andy.
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