The following questions related to how the supplementary equipotential bonding, is arranged with a typical Group 1 medical location room.
The attached sketch is provided to provide a visual representation of the Questions raised.
All questions relate to this element: 710.413.1.6.1 states that: In each medical location of group 1 and group 2, supplementary equipotential bonding conductors shall be installed and connected to the equipotential bonding bus bar for the purpose of equalizing potential differences between the following parts, located in the "patient environment": – protective conductors; – extraneous-conductive-parts;
Question 1 Conductive parts in the ceiling void
If metal pipework and ductwork is located in the ceiling void, but does not drop down to serve an outlet or appliance with the room, the patient environment’, do these services need to be provided with supplementary equipotential bonding?
Question 2 – False ceiling support grid
The patient zone defined in Figure 710A – Example of patient environment (IEC 60601-1), shows that 2.5m from floor to ceiling is defined as the patient environment, (however the 2.5m dimension is not prescriptive).
In a typical room if the ceiling grid is more than 2.5m above finished floor level, then can it be taken that it is outside the patient environment and does not require supplementary equipotential bonding?
Also, what defines the 2.5m, rooms of this type are typically 2.4m above finished floor level, as I would consider that could be deemed to be outside the ‘patient environment’?
Question 3 – Luminaires recessed into or fixed to the ceiling void
If the luminaires to the room are recessed, or surface within the room, and are not within the ‘patient environment’ is there a need to provide supplementary equipotential bonding? If the light switch that controls those luminaires falls within the ‘patient environment’ does that mean, the light switch should be bonded?
Question 4 – Supplementary equipotential bonding of general power circuits
PDF For the bonding a general power circuit, is it required only to provide a bonding cable from the equipotential earth bar to the first socket outlet, as it is assumed the remaining general power outlets will be bonded together by the circuit’s earthing cable?
