Air circuit breakers (ACBs) are the main protection on most LV switchboards and on every generator changeover and synchronising panel we build. If an ACB fails to close on a mains failure, or trips when it should not, the standby generator cannot do its job. PCAS Ltd provides ACB maintenance, testing and repair across Yorkshire, the North West and the rest of the UK from our base in Sheffield.
Our engineers work on the breakers found in commercial and industrial switchrooms, including Schneider Masterpact, ABB Emax, Terasaki TemPower and Siemens 3WL frames, along with older legacy units. We service breakers in situ or remove them to our workshop, and we can supply replacement and spare breakers through our breaker sales service.
ACB maintenance can be included in a generator service agreement with 24/7 callout, so the breakers, switchgear and generator are all looked after by one team.
Identifying Common Problems
ACBs suffer from wear on the main contacts and arc chutes, dried out lubrication in the closing mechanism, faulty shunt trips and undervoltage releases, and trip units that drift out of setting. Many breakers sit for years without operating, then fail the one time they are needed. Common faults we find include breakers that will not charge or close, racking mechanisms that seize, high contact resistance causing heat, and protection settings that no longer match the site.
Planned maintenance at the manufacturer’s recommended interval finds these problems before they cause a shutdown.
What We Offer
Our ACB maintenance service includes:
Every visit comes with a written test report for your maintenance records and insurer.
ACBs on Generator and Synchronising Panels
On standby and multi generator sites the ACBs are controlled by the generator controllers. We are ComAp specialists, so we test the full sequence: mains failure, generator start, breaker close, load transfer and return to mains. On synchronised and multi mains schemes we check the breaker feedback, close times and interlocks that the controllers rely on. See our ComAp specialist and complex power control schemes pages.
Recent ACB Work
Call 0114 317 7939 or email support@pcasltd.com for an ACB maintenance quote.
Our teams are headed up by Stuart and Nik Morley, who have a collective 50 years of experience in the power control, communications, and automation industries.
Our experience is our greatest asset and has allowed us to grow our company and reputation organically. Our independently run organisation allows for maximum flexibility during project delivery.
We welcome conversations with consultants, manufacturers, design and build companies, mechanical engineering companies, planners, project managers, and anybody requiring critical power solutions.
