lectures on Lab electrical system_Instrumentation Lect 2nd yr

PRINCIPLES OF ELECTRICITY

• Over all Lab electrical system • Lab electrical equipment Installation Laboratory equipment Safety

• Electric Shock And Personal Safety Personal Safety Guidelines First Aid List of common equipment

OVER ALL LAB ELECTRICAL SYSTEM - Dual sockets must be installed, 110v to support American system and 240v for the British system. The sockets must be clearly labeled preferably with different ink colors. - Dual 50/60 Hz cycles must be available. 110v equipment works on both cycles however 240v definitely requires 60 Hz. - Both types of sockets should be available on all of the bench tops. - At least three sets of sockets should be available on each wall of the laboratory. - 240v sockets and sometimes for extra safety 110V sockets must be earthed.

- 110v sockets must be either two pins round or flat face sockets and all 240v should be universal three pin flat face sockets. - Stabilizers must be connected to continuously running equipment in order to stabilize any electrical fluctuations - The main electric connection should be linked to a back-up generator as a compensatory mechanism in case of complete electrical failure.

- The fuse box should support the required electrical consumption of the equipment in the lab. In case this consumption exceeds the fuse capacity the fuse box must be changed. - The laboratory must have a circuit breaker Fuses as circuit breakers prevent over-heating of wires and components that might otherwise create fire hazards. They disconnect the circuit when it becomes overloaded.

LAB ELECTRICAL EQUIPMENT This is the most valuable item in the medical laboratory. Coulter Counter or Cell-Dyn may cost as much as $200,000 or a full Chemistry automodular may cost up to $300,000. Therefore their initial installation should be carried out very carefully. Other electrically powered equipment, such as hot plates, stirrers, vacuum pumps, electrophoresis apparatus, lasers, heating mantles, ultrasonicators, power supplies, and microwave ovens are also essential elements of many medical laboratories. If not handled carefully or not maintained, these can be damaged or can be hazardous to lab personnel particularly because they use large capacitors and high voltage .

Installation: - Dual voltage equipment should be preferred and this should be pre-adjusted to 240v. - Initially ask the dealer to install the equipment - Manual must be read carefully, and manufacturer’s guarantee must be clearly documented and placed in safe place. - Make sure the equipment is Switched-off before plugging in. - Check plugs and use adapters accordingly. - Extension wires should never be used on heavy duty equipment. - Light equipment such as centrifuges, incubator or water baths can be plugged to extension wire however maximum 20Amp fuse and minimum 10 Amp fuse is recommended in the plug. -

Much bigger fuse gauge e.g. 30 Amp allows high current to pass through un-noticed subsequently damaging the equipment. Too little fuse gauge