In general, electrical medical devices that include an applied part, SIP/SOP and mains need to ensure a certain degree of electrical isolation between each of these parts per electrical safety requirements (IEC 60601-1 - Medical electrical equipment - Part 1) to prevent the operators and patients from electrical shock. The image below depicts the applicable isolation zones required.
Explanation of each part of the electrical medical device depicted above is as follow:
- SIP/SOP - Signal Input/Output Part; part of the medical electrical device, not being an applied part (see definition below), intended to deliver or receive signals to or from other electrical equipment/devices, for example, for display, recording or data processing
- Mains - The part (electrical circuit) of the medical electrical device that is intended to be connected to the supply mains
- Applied Part - Is the part of the medical electrical device that in normal use necessarily comes into physical contact with the patient to perform its function
The isolation structure of the Nox A1 device and Nox C1 device in connection with an auxiliary device is depicted below.
The Nox A1 device is an applied part and is isolated with air from the Nox C1 device***. The Nox C1 device has SIP/SOP where you have the analog inputs, serial inputs, and the USB inputs.
Note that the mains isolation for the Nox C1 device is ensured by the use of medical grade power supply of certain type. Use of other power supply types than the one provided with the Nox C1 device and addressed in the Instruction for Use for the C1 device violates the isolation of the C1 device**.
It should be safe to create a medical device system by connecting the SIP/SOP of the Nox C1 device to the SIP/SOP of another auxiliary medical electrical device so far the auxiliary device complies with applicable electrical safety requirements*.
For example it is possible to connect the SIP/SOP of a Sentec Digital Monitoring System device (by use of serial output cable e.g.) to the SIP/SOP of the Nox C1 (serial input) given the Digital Monitoring System device complies with applicable electrical safety requirements for medical devices. In similar way it is possible to connect other auxiliary devices to the Nox C1 SIP/SOP as long as the data output of the auxiliary device is a SIP/SOP of a certified medical device*.
Note that all a uxiliary devices connected to the C1 device should be powered from a single power strip to ensure a common ground, to avoid ground potential difference skewing or distorting the signals*****.
Summary - Basic Rules
- Before connecting any device/equipment to the C1 device make sure the device/equipment to be connected is NOT an applied part (see definition of applied part above) - in this case additional isolation box is needed to ensure electrical .
- Before connecting an auxiliary device (example of auxiliary device….) to the SIP/SOP of the C1 device verify that the auxiliary device is compliant with the medical device safety standard IEC/EN 60601-1 AND the instruction for use accompanying the auxiliary device addresses this use
- Before connecting IT equipment (like PC, laptops) to the SIP/SOP of the C1 device make sure the IT equipment to be connected complies to the safety standard IEC 60950-1
Note: If in doubt whether the connection of an equipment/device/auxiliary device to the SIP/SOP part of the C1 device might result in any hazard including electrical hazard contact a qualified medical technician or the manufacturer of the equipment/device/auxiliary device to be connected before forming/set-up of the system
* Warning: External equipment and all auxiliary devices intended for connection to signal input, signal output or other connectors on the C1 device shall comply with the relevant product safety standards, e.g. IEC 60950-1 for IT equipment and the IEC 60601 series for medical electrical equipment, to prevent electric shocks. In addition, all such combinations – systems – shall comply with the safety requirements stated in the general standard IEC 60601-1, edition 3/3.1, clause 16. Any equipment not complying with the leakage current requirements in IEC 60601-1 shall be kept outside the patient environment, i.e. at least 1.5 m from the patient support. Any person who connects external equipment to signal input, signal output or other connectors on the C1 device has formed a system and is therefore responsible for the system to comply with the requirements. If in doubt, contact a qualified medical technician or your local representative.
**Warning: Only use power supply FRIWO MP115 Medical-7555M/12 with the C1 device. The use of an incorrect power supply may result in electric shock or cause the device to overheat, which may result in patient/operator harm.
***Warning: The USB channels, serial channels and analog channels on the C1 device are a part of the SIP/SOP for the medical electrical device and thus are NOT to be connected in direct galvanic connection to the patient under any circumstances. Violating this rule, e.g. by connecting the A1 device to the analog inputs on the C1 device may result in electric shock.
****No modification of the C1 device is allowed. Unauthorized modifications may affect data analysis and result in possible incorrect treatment or result in electrical shock.
***** Warning: Note that all auxiliary devices connected to the C1 device should be powered from a single power strip to ensure a common ground, to avoid ground potential difference skewing or distorting the signals, and thus prevent possible incorrect treatment.