Patient connection and accessible parts - enclosure

Jonssa

Registered
Hi everyone,

I'm very glad to be a member of this forum. I've already read a lot topics, but I'm still confused about some safety related issues. It is the first time I design ME device and first standard I have in my hands :)

I'm designing hand-held, Internally Powered device (3.7V Li-Po). The whole device is going to be used in home so it has to comply IEC 60601-1-11. Patient will hold and operate it with one hand, in the other he will have smartphone (BLE communication). The only applied part (and also only accessible) of ME device is an enclosure made of solid, insulating material. For charging, I want to use USB socket (only power, not insulated from secondary), which is located in the back of the device and during its INTENDED USE, the patient doesn't touch it, as well as enclosure around the USB. Furthermore the USB socket is not accessible part, its a bit hidden into the enclosure, something like in attached photo.


According to Subclause 3.8, if there applied part has no PATIENT CONNECTIONS, during tests insulated applied parts are covered with foil (Clause 8.7.4.7) and treated as PATIENT CONNECTION. Between enclosure and applied part (patient connection) there should be MOP.

a) Can somebody help me to understand, if I can divide the insulated enclosure on 2 parts: first as applied part and second (around USB) as enclosure (accessible part)? (Something like below)

b) If yes, how to define MOP between applied part and enclosure?
c) If no, should I treat whole encosure as applied part?
d) If whole enclosure is treated as applied part, should I use 2 MOPPs for USB socket as @5V, cr: 3.4 mm, cl: 1.6 mm or rather 1 MOOP for USB @250V, cr. 4mm, cl. 2.5mm (according to MAXIMUM MAINS VOLTAGE for internally powered devices, Clause 8.5.3)?
e) Could You tell me if i correctly understand the clearance/creepage distance in terms of USB to accessible parts? (Photo below)


Sorry that post is so long, but every time I think I figured it out, next obstacles occurs.

Thanks a lot for Your help.
 

VinceTech

Involved In Discussions
What type of Applied Part you need? B, F or C
Also, would the CD/AC remains sufficient under spillage test?
 

Jonssa

Registered
It must meet BF applied part requirements. Could You decrypt for me CD/AC? Equipment is not handling any liquids. I want to use IPx5 socket to prevent water ingress into ME Equipment during spillage
 

VinceTech

Involved In Discussions
Creepage Distance and Air Clearance.
my understanding is Enclosure can be AP, and AP can be enclosure. So for your device, requirements in enclosure and AP are applied, and may be no boundary between them.

Could you confirm if the USB charger device will be connected during use on patient? If so, what type of charger will be specified for use? for example, double insulated?
If charger connection is not permitted during patient use, I don't see there is need to provide MOP between AP/enclosure and USB connector. If charger connection is allowed, the assessment will need to include charger.

I don't know much about IP connector, does it provide MOP between connector pin and internal circuit?

the creepage shown on your drawing is along the surface of enclosure. if this surface is web, the creepage is shorted.


Just opinion. Anyone in forum have comments?
 

Jonssa

Registered
Thank You for Yours answer, I really appreciate it.

The device should not be charged during use on Patient (device turns off when connected, information in IFU, LED indication not to use device) so I assumed to use 2 MOOP protection when charging. Charger USB cable should be connected to 60950-1 (or 60601-1) compilant PC or PDU.

By IP connector I mean that it prevents water ingress into device, there is no galvanic isolation between USB and other secondary circuit
 

VinceTech

Involved In Discussions
Thank You for Yours answer, I really appreciate it.

The device should not be charged during use on Patient (device turns off when connected, information in IFU, LED indication not to use device) so I assumed to use 2 MOOP protection when charging. Charger USB cable should be connected to 60950-1 (or 60601-1) compilant PC or PDU.

By IP connector I mean that it prevents water ingress into device, there is no galvanic isolation between USB and other secondary circuit

Yes, 2MOOP shall be provided by a charger (e.g. double insulated charger).
 
Top Bottom