How to Do Busbar Inspection and Maintenance on Ships?

A busbar is a copper plate/bar which is used in ship’s main and emergency switchboards to conduct electricity from generators or from one electrical terminal to another. Technically, there are no electrical wire connections inside the main and emergency switchboards on ships for connecting Power supply from generators to these switchboards. All high voltage and high current systems are connected by bus bars.

The busbar’s copper plates/ bars are connected together with the help of nut bolts, which transmit electricity as required. During normal ship operations, the busbar connections are subjected to ship’s harsh environment along with the vibrations generated by the ship and ship machinery such as Main Engine, auxiliary engines, compressors etc. These vibrations cause loosening of nut bolts in the busbar, which can lead to short circuit or any other type of accident. Loose connections inside the switchboard can also lead to sparks that can cause fire.

Moreover, the busbars are meant to carry high voltage and current which tend to heat up the lines due to energy flow in the system. For this reason, inspection and maintenance of busbar at regular inspection of time are required for smooth operation.

busbas inspection and maintenance
Busbas inspection and maintenance


If any maintenance is planned for busbars, highest standards of safety are required as even the tiniest mistake can lead to electrocution and even death. The busbar maintenance is therefore performed when the complete busbar panel or Switchboard is turned “OFF”. Following are the precautions for safety to be carried out when the bus bar maintenance is to be carried out:

When the bus bar maintenance should be done?

  1. Bus bar maintenance can be done when the ship is in black out condition, i.e. ship’s generators are not running and no power is supplied to main or emergency switchboards
  2. If the main switchboard busbars are to be inspected or to be work on, keep emergency generator running. Keep in mind that there will be some portion of the main switchboard which will be fed by emergency switch board. Hence know the complete system properly and keep away from those areas
  3. The best time to do bus bar maintenance is when the ship is in the dry dock

Safety before doing bus bar maintenance:

  1. Put the “lockout” tag in all generators and in the emergency generator
  2. Keep all the generator system including load dependent start stop system in manual mode
  3. Ensure to wear rubber gloves even when the board is not in “Live” condition
  4. Wear all required personal protective equipment (PPEs) when working on switchboard
  5. If the ship is in complete black out situation, ensure that before cleaning the main and emergency switchboard, the area is well lit by sufficient lights.  In dry dock same can be arranged from shore workshop

How Busbar Inspection and maintenance is carried out?

Any maintenance on busbars should only be performed when the ship in Dry dock or Black out condition:

  1. Open the door for main and emergency switchboards where inspection is to be performed
  2. Carryout visual inspection of copper plate and nut bolts. Mark any missing or burn out areas
  3. By hand or using a metal or plastic stick (where access for hand is not possible), tap the bus plates gently so as to make out for any loose connection. Ensure to wear electrical gloves even when bus bar is not live
  4. The busbars are mechanical supported inside the switchboard by means of insulators, which may be of rubber or ceramic materials (bad conductors). Check for any damages in the insulator part
  5. By using only dedicate size spanner or pre adjusted torque wrench, tighten the nuts in the busbar connection for main and emergency switch boards
  6. Check the tightness of the wire connections, which is connected to the circuit breakers
  7. Clean the bus bar and switchboard area with the help of vacuum cleaner
  8. If u find any loose connection or spark, black-out the particular and adjacent bus bar before tightening the nut
  9. If u find any metal piece or nut bolts missing or inside the panel, ensure to remove it as the same can cause short circuit or fire
Busbar connections
Busbar connections

The ship’s electrical officer is required to inspect the busbar periodically for record keeping and also as stated by the preventive maintenance system. This is done to avoid any type of accident from electrical faults on ships. When doing such inspection the following highest safety measures are to be taken with all required PPEs as the Bus bar is “LIVE”:

  • Check the load in the running generator by means of KW meter provided in the main switchboard.
  • Open the bus bar access door provided at the backside of MSB or ESB.
  • Do the visual inspection and by the help of infrared temperature gun, measure the temperature of copper plates and bus bar connection.It should not be more than given limits depending upon the generator load. Example if the generator load is 50%, the room temperature is 28 deg c, the bus bar temperature must be within 50 deg c, if the temperature is too high then some thing is abnormal.

Once the inspection and maintenance is completed:

  1. Close the bus bar access doors
  2. Remove the lock out tag
  3. Restore the main power supply by the generators
  4. Inform the Chief Engineer and the in-charge of that particular machinery regarding the same
  5. Reset the main power and check if there is any abnormal sound in main switch board and emergency switch board
  6. Monitor the temperature of the busbar area with laser temperature gun
  7. Keep the emergency switchboard in the auto mode

How do you carry out busbar maintenance on board ships? Let us know in the comments below.

Do you have info to share with us ? Suggest a correction

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  1. Dear sir

    I want to ask a question

    Why marine electric busbar is composed of mor than one part and can be connected by circuit breakers ?

  2. No mention of doing thermographic surveyey while the vessel is in service? This is a valuable way of finding faults before they escalate. also class usually accepts this.

    There is also the method of ductor testing which can find weak connections in the switchboard.

    Also, the use of an adjustable spanner to tighten bus bar connections is laughable. The correct method would always involve use of the proper size tools, ie torque wrenches with the correct size sockets. You should find this torque in your switchboard manual or get the information from the manufacturer.

  3. The new way to do this is continuous online temperature monitoring. It’s vastly superior to routine maintenance and thermographic inspections and furthermore is also more economical with the next generation of technology available.

    In Naval applications electrical maintenance is absolutely necessary to ensure the safety and reliably of equipment. Connector reliability is published in MIL-HDBK-217F [1] showing sheltered (below decks) electrical connections are as much as 6 times more likely to fail than in benign, ground based environments.

    PyrOptic is the most optimised solution in the world for catching deteriorating connections in electrical equipment prior to catastrophic failure. Many other technologies exists however none come close to the economy, scalability or underlying reliability that our technology offers. From low voltage motor control centres through to medium voltage 30kA phase isolated bus systems, it’s all the same as far as our technology is concerned.

    PyrOptic has already found it’s way in to marine electrical systems!

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