Electrical resistance testing a cardiac protected operating theatre in a day hospital - Fluke 1664FC

This description is a massive wall of text but I felt that I needed to give a little context to the videos content. Enjoy the ride or the read or both hah!

My instagram -   / willmannelectrical  

Follow along with some of the preliminary testing I've been doing on my cardiac rated operating theater. Ceiling should be sheeted soon and I needed to check that everything is up to code as per AS3003:2018 the Patient Areas standard.

This is a link to a document that gives a general guide to this standard If you are interested in this topic, its pretty in depth and for the most part I'm self taught in this area.

https://electricaltestingcompany.com....

Here are a few key definitions:

Cardiac-protected electrical area: where the procedure involves direct connection to the
heart, RCD or isolation transformer protection, similar to that required for a body-protected electrical
area, is supplemented with special earthing facilities to also provide protection against ‘microshock electrocution’. Such a system not only protects against any fault or leakage currents posing a macroshock hazard, but also reduces the potential difference appearing between any conducting surfaces in the vicinity of the patient (electrically-operated equipment, plumbing, structural metal and similar) to a level well below that which would produce microshock electrocution

Definition of Equipotential Bonding from AS/NZS 3000:
Electrical connections intended to bring exposed conductive parts or extraneous conductive parts
to the same or approximately the same potential, but not intended to carry current in normal service. Exposed conductive part: a conductive part of electrical equipment that can be touched with the standard test finger, and is not a live part but can become live if basic insulation fails. (exceptions apply, including double insulation, refer AS/NZS 3000 for the complete definition)
Extraneous conductive part: a conductive part that does not form part of an electrical installation but that may be at the electrical potential of a local earth. Examples include the following –
(a) Metal waste, water or gas pipe from outside.
(b) Cooling or heating system parts.
(c) Metal or reinforced concrete building components.
(d) Steel-framed structure.
(There are further examples refer AS/NZS 3000 for the complete definition)



A few key clauses related to this video.



CL.4.4.2.10 – (cardiac bonding) The earth resistance between the EP test terminal and the EP junction or node shall have a maximum value of 0.01Ω.

CL.4.4.2.4.2 – (cardiac bonding) Socket-outlet protective earthing conductors shall be insulated from other conductive items except at the EP junction. The resistance between the socket earth pin and the EP test point or node shall not exceed 0.1 ohm.

CL.4.4.2.5.3 – (cardiac bonding) A separate earthing conductor shall be used to connect each item of permanently wired electrical equipment to the EP junction or node. Permanently wired electrical equipment includes such items as electrical wall boxes, medical service panels, pendants and pedestals, metal cable
enclosures.

CL.4.4.2.5.5 – (cardiac bonding) The resistance of any earthing conductor installed between any socket outlet or any item of permanently wired electrical equipment and the EPJ or node shall not exceed 0.1Ω.
Note: Permanently installed electrical equipment that is inaccessible in the patient environment need not comply, this equipment may be earthed directly to the distribution board.

CL.4.4.2.6 – (cardiac bonding) Permanently installed non-electrical conductive equipment and fittings that contact structural metal shall be connected to the EPJ or node via individual earthing conductors having a resistance not exceeding 0.1 ohms.
• Medical gas outlet reticulated pipelines may be earthed via pipe cable clamps or a braised copper strap with a cable lug connection.
• Water and drainage reticulated pipelines may be earthed via pipe cable clamps.
• Window frames may be earthed via the underlying fixed metal frame that contacts the structural
metal.
• Air conditioning grills may be earthed via the underlying fixed metal frame that contacts the structural metal.
• Monitor brackets, hand and equipment rails etc. may be earthed via the underlying metal wall frame that contacts structural metal. Non-electrical conductive fittings are regarded as contacting structural metal if the resistance to theEPJ or node is less than 1 MΩ when measured at 500V DC (megger test.)




#electrician #construction #sparky