Why Contactor-Based ATS Panels Are Failing Modern Food Plants – And the Safer, Smarter Alternative

Modern food processing plants demand absolute reliability. A short power interruption can stop an entire production line, force a full system reset, and risk product integrity or hygiene compliance. Yet many sites are still relying on older-style contactor-based Automatic Transfer Switch (ATS) panels that simply aren’t up to the job.

Poorly Manufactured Contactor based ATS Panel

We were recently called to a modern food processing facility where the existing ATS was causing repeated problems. The plant was experiencing nuisance tripping on very small brown-outs. Even a brief dip in the mains voltage was enough to drop the contactors, cutting power to the whole processing line and requiring a complete reset. The cost in lost production and downtime must have been significant.

When we opened the panel, the issues went beyond reliability:

• The top of the contactors were only 15–20 mm from the back of the door

• Heavy 185 mm² HO7 Tri-rated cables were connected with no shrouds or protection

• Overall construction quality was poor, leaving live parts inadequately guarded

This combination of tight clearances and unprotected terminations is a clear safety concern and falls well short of good engineering practice.

The Limitations of Traditional Contactor ATS Panels

Contactor-based systems rely on electromagnetic coils to hold the contacts closed. When the mains voltage dips even slightly, the coil can drop out. This creates several problems:

• Frequent nuisance tripping on brown-outs or phase instability

• No ability to stay on mains during minor voltage fluctuations

• Limited control over transfer conditions (total loss vs phase or neutral loss)

• Dependence on the coil remaining energised – if the coil fails, you can lose the ability to switch

• Often poorer mechanical interlocking and less robust construction

In a food plant, these issues translate directly into lost production, wasted product, and unnecessary stress on both staff and equipment.

A Better Solution: C&D Mercia Switch-Based ATS Panels

We recommended replacing the existing panel with one of our top-specification ATS panels built around a C&D Mercia changeover switch. These panels are designed, built and installed by GES Power to a high standard of safety and reliability.

Key advantages of this approach include:

1. Superior Control Over Transfer Conditions The system can be configured to transfer to generator on:

• Total loss of mains

• Loss of a single phase

• Loss of neutral

This gives the operator far more precise control than a simple contactor arrangement.

2. Manual Operation Capability Because the heart of the panel is a robust mechanical changeover switch rather than a contactor coil, the operator can manually switch between mains and generator if required. You are no longer completely dependent on an electromagnetic coil remaining energised.

3. Improved Reliability and Reduced Nuisance Tripping The Mercia switch and associated control logic are far more tolerant of short-duration brown-outs, dramatically reducing unwanted transfers and the associated production resets.

4. Safer Construction and Installation Our panels are built with proper clearances, full shrouding of live parts, correctly rated and protected cabling, and professional installation. No more 15–20 mm gaps to the door or unprotected heavy cables.

5. Built for Critical Applications These panels are engineered for continuous industrial duty and are particularly well suited to food processing, cold storage and other environments where downtime is costly and safety is non-negotiable.

Features & Benefits at a Glance

Feature	Contactor-Based ATS	C&D Mercia ATS (GES Power)
Nuisance tripping on brown-outs	Common	Significantly reduced
Transfer on phase/neutral loss	Limited or none	Fully configurable
Manual switching capability	Usually none	Yes – mechanical switch
Dependence on coil	High	Minimal
Mechanical interlocking	Often basic	Robust and positive
Safety clearances & shrouding	Frequently inadequate	Designed and installed to high standard
Overall reliability	Variable	High – built for industrial duty

Why This Matters in Food Processing

In a modern food plant, power reliability is not just about keeping the lights on. It protects product quality, maintains hygiene processes, and prevents expensive line resets. A poorly performing ATS can turn a minor voltage dip into a major production stoppage.

By upgrading to a properly engineered C&D Mercia switch-based panel, operators gain:

• Greater control over when and how the system transfers

• The ability to intervene manually if needed

• A safer installation that meets modern standards

• Reduced risk of nuisance trips and associated downtime

Ready to improve the reliability and safety of your standby power system?

GES Power designs, builds and installs high-specification ATS panels featuring C&D Mercia switches. We provide complete turnkey solutions including site survey, design, manufacture, installation and commissioning.

Call us on 01246 380525 Email hello@generator-man.co.uk

GES Power Ltd – Specialist providers of diesel generators, high-quality ATS panels and 24/7 support across the United Kingdom.