Question. In BS7671 what reg states about proving dead? Also about locking off?

Question. In BS7671 what reg states about proving dead? Also about locking off?

  • Graham will probably be on in a mo to say that symbol of a triangle with a circle in it is not the right sort of ground symbol for equipment like that To me it would read as 'ground zero' on a circuit.

    See pages 20 and 25 of the instruction book.

  • Thanks Chris

    Assuming that an appropriate lead is available then a short lead from the bonding point to the light over the table would do the trick and avoid a trip hazard?

    Can I push my luck and ask why everything the clinicians attach to the patient is connected to the medical IT system and why the table the patient is laying on is a 230V Class 1 appliance, albeit hopefully bonded to the EBB?

    JP

  • Hi John. Would an IT socket  provide power to a table employed for patient examination or treatment in a Group 2 medical location. Additionally, the table should be a Class 1 appliance with earth protection and should be connected to the equipotential bonding bar (EBB) to minimize the potential difference between various metal parts that may contact the patient or staff.

  • Well that's a new one 'potential equilization conductor'

    EEB then to supplement the ADS ;-)

    Mike.

  • Graham will probably be on in a mo to say that symbol of a triangle with a circle in it is not the right sort of ground symbol for equipment like that To me it would read as 'ground zero' on a circuit.

    But then again, he might come along and say "If it's not a protective or functional earth connection, say because the product has Class II or similar construction, but the terminal is used to prevent static build-up or help equalize potential (behind which is a normally unhazardous current, but one that might be uncomfortable for patients, or cause involuntary muscle reactions or a perceptive reaction) that might be caused by capacitances or leakage across the insulation of the class II insulation, then it really is the correct symbol IEC 60417-5021: ">www.iso.org/.../ui

    Well that's a new one 'potential equilization conductor'

    If you call 1977 new (date from the IEC 60417 entry linked above). Used on medical electrical equipment quite regularly, also seen it on other electronic systems where you might have a similar issue.

    The wheelie bin is much newer. Its use (in EU and member-state legislation) is older than its entry IEC 60417 -6414, which was made in 2019.

  •  Resus ward , medical bed head trunking. You can just about see the symbol.

  • As JP suggests, I bet that it has never been used.

    I wonder whether this facility is present in order to comply with an international standard which might be more appropriate elsewhere.

  • Can I push my luck and ask why everything the clinicians attach to the patient is connected to the medical IT system and why the table the patient is laying on is a 230V Class 1 appliance, albeit hopefully bonded to the EBB?

    A fixed operating table is one of the exceptions in 710.411.6. Given that it is planted in the fabric of the building, it would seem rather counterproductive to supply it via the IT system.

    Frankly, I see nothing wrong with an unpowered table. Wheel it in and apply the parking brake. Pump up with an hydraulic mechanism similar to a barber's chair. Adjust for tilt, etc. using a hand wheel as found on a lathe.

    In any event, if you have day surgery nowadays, you will go nowhere near a bed or an operating table. Turn up bright and early. Undress, put on your dressing gown back-to-front and jump on a trolley where you stay until going home time.

  • Hello Sergio, if you’re looking for safety guidelines for live working and working on LV made dead, I recommend reading HTM 06-02.