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SIP/SOP - Mains Power and Medical Device Ethernet Ports

#11
With respect to the patient, if the medical equipment has Type F insulation (BF, CF) or if the SIP/SOPs are earthed or there is an earthed intermediate circuit, then there is really no potential harm from SIP/SOPs.
Hi Peter,

The "earthed" you mentioned is not for "protectively earthed" only, right?

The intermediate circuit including the SIP/SOPs is normally earthed but will definitely fail the impedance and current-carrying test which based on earth fault of mains side (cl. 8.6.4).

In practice, SIP/SOPs should not be subject to high current testing unless the fault source is unlimited (but that is not true). Unfortunately, the standard seems to apply an unlimited mains source on the SIP/SOPs (the resistance in Figure 14 is optional and is just to protect the person performing the test).
 
#12
Yes, the earthed only needs to be sufficient to divert leakage currents (mA) to ground, not fault currents (Amps). Normal "functional" earthing is enough for this.

If the test is performed according to Clause 16, it means testing the actual system, not the "mains on SIP/SOP" test.

If you have two earthed devices A and B, both separately plugged into the wall, which are then connected together via an earthed signal connection, and the earth in device B is broken, the leakage current will flow via the signal cable through the earth of device A and back to the wall, not to the operator or patient. There may be double leakage, exceeding 0.5mA, but the leakage is not able to get to the operator/patient without a second fault which is not considered by the standard.

The test can be considered hypothetically if the actual system is not known.
 
A

antonoia

#13
Hello everybody,
I see there are different opinions regarding this point, so I will give mine too and see if you agree. Definition of SIP/SOP states that is applicable for connections intended to other electrical equipments. A lan port connected to a third device will not ensure any kind of insulation, and so the test will be still applicable. If the device is provided with more than one port , you can apply the main voltage on all of them temporarily or once at a time, is always under the single fault condition philosophy, depend from the fault extension. I appreciate Peter's opinions I think in some cases standards requires more than what is the real world. But I am not still sure if the test will be still applicable to a device (in a ME system or not) of which specifications are defined. Waiting for yours , Regards!
 
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