A busbar is a copper plate or bar which is used to conduct electricity; they are typically used in a ship’s main and emergency switchboards to handle the high voltages of electricity coming in from the generators.
Why do these Bars need Frequent Maintenance when Present on Ships?
Busbars on ships are are particularly vulnerable to damage as they are subjected to the rigours of sea travel: Harsh marine environments (which stress the entire body of the vessel) and the constant vibrations of the ship itself. These vibrations are notorious for loosening the various connecting nut bolts of the bars, which can lead to short circuits, fires, and other accidents.
For such reasons as these, as well as the smooth operation of the ship, regular busbar maintenance aboard seagoing vessels is a must. Due to the high voltage involved, one must be extremely thorough about safety.
How are Busbars Maintained on Ships?
Each ship should have its own detailed procedure to regarding how to safely maintain all of its electrical components, but as a general overview, many ships utilise the following safety practices when checking on the status of their busbars:
The complete busbar panel or switchboard is turned off before any maintenance is performed. The ship’s generators are not running and no power is supplied to any of the switchboards, even the emergency switchboard; this is known as having the ship in “black out” condition, and it’s best done when the ship is in a dry dock state.
The “lockout” tag is then placed on all generators and the entire generator system is set in manual mode. The maintenance person dons rubber gloves as an extra safety precaution, despite the board not being “live” at the time, and wears all of the suggested personal protective equipment (PPEs). As the ship is in a “black out” state, ample temporary lighting is provided.
A visual inspection is then performed on the main and emergency switchboards, taking special care to note the condition of the copper plate and nut bolts, tightening any bolts as necessary. The maintenance person will then look for missing or burned out areas, either by hand or through the use of a metal or plastic stick, before moving on to check the insulators for signs of wear or damage.
If everything checks out well enough, the switchboards will be cleaned, generally with a vacuum cleaner.
The ship’s electrical officer is also required to periodically inspect the busbars and keep detailed records as to their condition; this is part of a strategy of preventative maintenance that is meant to help the ship’s staff avoid all possible electrical accidents before they happen.
This type of inspection is even more risky, as it is often done when the system is “live”. A visual inspection is performed, then an infrared temperature gun is used to measure the temperature of the copper plates and the various busbar connections. The temperatures found must conform to the limits specified for the generator load; temperatures that are in excess of what is expected for the generator load and room temperature are often a clear sign that something is seriously wrong with one of the components being inspected.