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BS 7671 interpretation of clause 560.7.7

MS01
Within BS7671 there is the following clause:-

560.7.7 Safety circuit cables, other than metallic screened, fire-resistant cables, shall be adequately and reliably separated by distance or by barriers from other circuit cables, including other safety circuit cables.

Now I read this in two ways, the first is this is specifically talking about fire rated cables only… or

This is insinuating that unless I use a metallic screened fire-resistant cable I must provide separation by distance or by barriers including from other safety circuit cables. Does this mean a common dedicated medical IT final circuit trunking is not acceptable as each IT circuit in its own right is a safety circuit, therefore if I was to move away from fire rated cable I would need to ensure each IT circuit is installed in its own individual piece of containment (conduit) to give the correct level of separation or would a common galvanised trunking dedicated to the IT cabling be sufficient.

I appreciate no one will give me an answer to the question above, but can people let me know how they interpret this clause to see if I’m on the right lines.  

Can I ask how do you interpret this clause?

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  • 0
    The case of a medical IT system is somewhat different.


    A first-fault on the system may well simply cause an alert, but the system keeps going ... to power medical equipment that may well be keeping a patient alive (but this is not always the case). A second fault on the system (any circuit) may cause the operation of the protective device on that circuit alone. The medical IT system is not intended on its own to protect the patient from electric shock, it is used in this manner to provide continuity of supply and alert medical staff on first-fault, so first-fault doesn't take out a circuit, or the whole system.


    As to the particular protection requirements for a specific installation, it's important to understand what the medical IT system is achieving (i.e. what clinical procedures are being carried out, and what the powered equipment is intended to do).


    The situation is further complicated by the requirement to understand what any evacuation policy will be whilst patients are being treated, during a fire situation - so I guess you will get different answers for different situations.


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  • 0
    The case of a medical IT system is somewhat different.


    A first-fault on the system may well simply cause an alert, but the system keeps going ... to power medical equipment that may well be keeping a patient alive (but this is not always the case). A second fault on the system (any circuit) may cause the operation of the protective device on that circuit alone. The medical IT system is not intended on its own to protect the patient from electric shock, it is used in this manner to provide continuity of supply and alert medical staff on first-fault, so first-fault doesn't take out a circuit, or the whole system.


    As to the particular protection requirements for a specific installation, it's important to understand what the medical IT system is achieving (i.e. what clinical procedures are being carried out, and what the powered equipment is intended to do).


    The situation is further complicated by the requirement to understand what any evacuation policy will be whilst patients are being treated, during a fire situation - so I guess you will get different answers for different situations.


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