Multiple socket-outlets - Medical Device Electrical Equipment

EMengineer

Involved In Discussions
Good day,

I stuck with multiple socket-outlets. There is a medical supply unit with multiple socket-outlets (MSO). These socket outlets are Type F of domestic AC socket outlets (usualy used in Europe) which can accept mains plugs. According to EN 60601 3.1 edition 16.9.2.1a) cl. mutliple socket outlet:
Only allow connection by using a tool, or
Be of a type that cannot accept mains plugs of any of the kinds specified in IEC/TR 60083, or
Be supplied via a separating transformer.

None of these requirements are complied. There is no separating transformer or connection by using a tool.
Although, I have found the same connections of MSO in two different manufacturers. Here is the schematic diagram:

EM equipment.png
Is such connection considered as MSO, or is everything OK here?
 

EMengineer

Involved In Discussions
After some discussion with manufacturer I've got the asnwer: yes the equipment should comply with 15.9.2.1 requirements. Although there is no separating transformer, the mains (in hospital) is supplied via separating transformers, if not the manufacturer uses other socket outlet which cannot accept mains plugs of domestic devices.
 

Marcelo

Inactive Registered Visitor
Please note that, from the standpoint of IEC 60601, you cannot use any safety feature in the mains to protect the equipment (some other IEC standards do allow for that, but not IEC 60601).
 

EMengineer

Involved In Discussions
Please note that, from the standpoint of IEC 60601, you cannot use any safety feature in the mains to protect the equipment (some other IEC standards do allow for that, but not IEC 60601).
Thank you for information. Could you write which clause mentions that? I would like to improve my knowledge.
 

Marcelo

Inactive Registered Visitor
It's not clearly described anywhere in the standard, but it does not to, as the only options for protection against electric shock are class I and II equipment, both which do not require protection on the installation. You can see pointers in (60513 does mention it directly):

A.2 Safety of ME EQUIPMENT and ME SYSTEMS
BASIC SAFETY and ESSENTIAL PERFORMANCE of ME EQUIPMENT and ME SYSTEMS, as described in IEC/TR 60513 [12], are part of the total safety situation, comprising safety of ME EQUIPMENT, safety of the installation to which the ME EQUIPMENT or ME SYSTEM is connected and safety of application.

Subclause 6.2 – Protection against electric shock
The term “Class III equipment” is used in some other standards to identify equipment that is powered from a safety extra-low voltage (SELV) mains supply system. The term Class III equipment is not formally used in this standard. The BASIC SAFETY of Class III equipment is critically dependent on the installation and on other Class III equipment connected thereto. These factors are outside the control of the OPERATOR and this is considered to be unacceptable for ME EQUIPMENT. Additionally, limitation of voltage is not sufficient to ensure safety of the PATIENT. For these reasons, this standard does not recognize Class III construction.

If you want to understand general requirements for protection against electric shock, you should read:
Electrical Installations in Buildings
- IEC 60364-4-41, Electrical installations of buildings – Part 4-41: Protection for safety – Protection against electric shock and
- IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1: Principles, requirements and tests
 

mehrnaz

Starting to get Involved
I have the same issue as EMengineer in multiple socket outlets. there is a device which has to be tested in accordance IEC 60601-1 but there is not isolating transformer and normal plugs can be connected to outlet, a you mentioned it is not true to rely on hospital installation how it should be conformed?

I have read annex I of IEC 60601-1 table I.1 and it is the same as situation number 1e which is stated it can be an additional protective earth connection. but what is additional protective earth? is it insulation class II ?

thanks in advance
 

Marcelo

Inactive Registered Visitor
An additional protective earth connection is another connection to the protective earth terminal 9third pin, for example) that functions as a protective measure - see definition 3.94.
 

mehrnaz

Starting to get Involved
An additional protective earth connection is another connection to the protective earth terminal 9third pin, for example) that functions as a protective measure - see definition 3.94.

Mr.Antunes
thanks for your response, I am familiar with protective earth but the term additional made me to search more about it. does it mean that the device shall be class II and additionally shall have protective earth?
I am talking about a patient service console which is used in hospitals and has 3 gas outlets and 3 multiple socket outlets for medical and non medical devices connection and also used an adaptors for 2 lamps in it for lighting.
I am not sure as it conforms to IEC 60601-1?
because there is no isolating transformer in it for multiple sockets outlet and there are normal sockets.
 

Marcelo

Inactive Registered Visitor
The problem its not the term protective earth itself, but what is a protective earth connection - this is what can be additional. So you can have an additional link to the protective earth terminal as a way to solve the problem.

No, it has nothing to do with classe II devices because class II devices do not have protective earthing.
 

mehrnaz

Starting to get Involved
thanks for your response
one of Colleagues told me that I did not understand what you meant in the last post well. so I made the diagram of the circuit I think means by additional protective earth according to annex I of IEC 60601-1.
I suppose that I have to consider another link for Earth connection of Socket outlets(by the green line). am I correct?
Earth-connection-1.png
 
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