Replace the entire switchgear or just the circuit breaker?

If the CD player in your car died, would you pull out the entire instrument panel to replace it?

If the CD player in your car died, would you pull out the entire instrument panel to replace it? Of course not. You’d simply extract the old device and insert a new, perhaps upgraded, model that fits in the same compartment. If the built-in microwave over your range stopped working, would you pull down the whole wall? That would be ridiculous. You’d just install a new oven of the same dimensions, attaching it to the existing brackets.

So, what happens when outmoded circuit breakers in the switchgear of a marine vessel begin malfunctioning? Does it really make sense to replace the entire switchgear? Rarely. You may be able simply to replace the moving parts of the breakers with a retrofit solution.

While the most complete solution is to replace the entire switchgear, such a decision would make as little economic sense as ripping out a vehicle’s entire dashboard to replace a faulty CD player. Perhaps the size of a new switchgear could be reduced, but the handling space is often extremely small, possibly eliminating the option of replacing the complete switchgear.

Usually, the pure structural work of the switchgear will have a longer life than its circuit breakers, which are the most stressed components of the switchgear because of their mechanical and electrical opening operations.

If the circuit breaker model is no longer available in the market, the manufacturer may offer “retrofitting kits” that enable a rapid adaptation of new-generation circuit breakers to the old electrical switchgear. Using these kits is much like sliding a newer, smarter microwave into that space above your cooking surface.

The simplest concept of retrofitting solutions are hard-bus retrofill kits that require the complete replacement of the circuit breaker (both the fixed and the moving parts in the case of a withdrawable circuit breaker, only the circuit breaker in the case of a fixed installation) with a new-generation circuit breaker provided with the appropriate copper connections in various sizes in accordance with the different sizes/ terminals/currents to adapt new terminals to existing bus bars. Since the circuit breaker is more compact, the retrofitting kit is completed by the insulating bulkhead to avoid direct access to powered parts and adaptation of the switchgear’s cover panel.

This solution, however, inevitably requires significant downtime–4 to 8 hours for large circuit breakers–and accessing the switchgear both from the front and from the back.

Obsolete circuit breaker in switchgear:

Last-generation circuit breaker with retrofitting kit:

This solution may not be feasible if the circuit breaker is assembled in switchgear leaning against a wall or against other switchgear back-to-back.

For obsolete circuit breakers in a removable installation and with a fixed part in good condition, more advanced and faster implementation retrofit solutions are available, such as cradle in cradle and direct replacement.

Cradle in cradle – When the circuit breaker to be replaced is considerably bigger than the last-generation one, this simple but effective solution provides a kit to install the fixed part of the new circuit breaker in the fixed part of the obsolete circuit breaker. The two fixed parts become a single piece. The moving part of the new circuit breaker is normally racking-in and -out. Assembly time is reduced to a few hours.

Obsolete circuit breaker in switchgear:

Last-generation circuit breaker with retrofitting kit:

The panel door of the switchgear must be adapted to the new circuit breaker.

Direct replacement – This is the fastest solution. The moving part of the new breaker replaces the moving part of the obsolete breaker. The new breaker is appropriately modified to be racked-in the existing fixed part.

The wiring of the main accessories is pre-arranged.

This solution may be implemented in a very short time.

Last-generation circuit breaker with retrofitting kit:

This solution also requires the panel door of the switchgear to be adapted to the new circuit breaker.


Retrofitting kits offer many benefits:

  • Updating the switchgear by replacing only the circuit breaker
  • Better specifications and construction details of the new circuit breaker
  • Integration into the circuit breaker of devices such as ammeters and voltmeters with a high measurement accuracy
  • Remote supervision with new communication modules and protocols
  • Better safety with new key locks
  • Longer product availability and multiple-year support.

Retrofitting kits for marine vessels may be the perfect solution to keep your budget and schedules afloat.

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About the author

Valeria Cornelli

I am Global Product Service Manager for ABB’s Protection and Connection business. I started as Global Product Manager in 2007 and reached my position in 2010, cooperating in the creation of the new PM team dedicated to Service for ABB Low Voltage Circuit Breakers. After 7 years my job is still stimulating, challenging and exciting. The aim of the group I work with is to find new Service products and solutions to fulfill and anticipate customer’s needs. Outside the office, I have lots of hobbies: tennis, cake design, my family, friends and animals.
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