Why Your Commercial Dishwasher Keeps Tripping: Common Electrical Issues Explained

What Does “Tripping” Mean?

When a commercial dishwasher “trips”, it usually means the circuit breaker or residual current device (RCD) has shut off power to protect the electrical system. This safety mechanism activates when it detects:

• Electrical overloads
• Short circuits
• Earth leakage
• Unsafe current flow

In commercial kitchens, where equipment runs for long hours under heavy demand, these problems are more common than most realise.

 

What Does Electricity Leaking To Earth Mean?

Electricity leaking to earth means electric current is escaping its intended, insulated path and flowing into the ground (or a grounded object) instead of returning through the neutral wire.

 

Faulty Heating Elements

One of the most common causes of tripping in commercial dishwashers is a failing heating element.

The heating element is responsible for bringing water up to sanitising temperatures, often around 82°C. Over time, constant exposure to heat, limescale, and moisture can damage the element’s insulation. When this happens, electricity can leak to earth, causing the RCD to trip.

Signs of a Faulty Heating Element:

• Dishwasher trips during the heating cycle
• Water doesn’t reach proper temperatures
• Burning smells or visible scorching
• Longer wash cycles than usual

In hard-water areas, limescale buildup can significantly accelerate wear on heating components.

 

Water Leakage into Electrical Components

Commercial dishwashers operate in high-moisture environments, making water leakage a major risk.

Leaks from seals, pumps, hoses, or spray arms can allow water to reach electrical wiring, terminals, or control boards. Even small amounts of moisture can create short circuits or earth faults that trip the system.

Common Areas Where Water Causes Problems:

• Damaged door seals
• Leaking wash pumps
• Loose pipe connections
• Condensation inside control panels
• Cracked hoses

Because commercial machines often run continuously during busy shifts, even minor leaks can quickly become serious electrical hazards.

 

Overloaded Circuits

Commercial dishwashers require substantial power, especially high-temperature models. If the machine shared a circuit with other heavy-duty catering equipment, the electrical load may exceed the breaker's capacity.

This is particularly common in older kitchens where electrical infrastructure has not been upgraded alongside newer equipment.

Equipment That Often Causes Circuit Overloads:

• Combination ovens
• Fryers
• Glasswashers
• Fridge/freezers
• Water boilers

When multiple appliances draw power simultaneously, the breaker trips to prevent overheating or fire risk.

 

Damaged Wiring or Loose Connections

Kitchen environments expose wiring to heat, steam, vibration, grease, and cleaning chemicals daily. Over time, this can damage insulation or loose electrical terminals.

Loose connections create resistance and heat buildup, whilst damaged cables may short against the metal parts of the dishwasher.

Warning Signs of Wiring Problems:

• Intermittent tripping
• Flickering display panels
• Buzzing sounds
• Burning odours
• Visible cable wear

These faults should always be inspected by a qualified engineer or electrician.

 

Failing Wash or Drain Pumps

Commercial dishwashers rely heavily on motor-driven pumps to circulate and drain water. As pumps age, internal motor windings can deteriorate or seize.

A failing motor often draws excessive current during startup, causing breakers to trip repeatedly.

Symptoms of Pump-Related Electrical Issues:

• Humming noises without water movement
• Tripping during draining cycles
• Poor water circulation
• Slow draining
• Machine stopping mid-cycle

Ignoring pump problems can eventually lead to complete motor failure.

 

Control Board or PCB Faults

Modern commercial dishwashers use electronic control boards (PCBs) to manage wash cycles, temperatures, dosing systems, and diagnostics.

Power surges, moisture, and age can damage these sensitive components. Faulty boards may send incorrect signals or cause internal short circuits.

Common Indicators of PCB Problems:

• Random shutdowns
• Error codes
• Inconsistent cycle behaviour
• Tripping without obvious mechanical issues
• Unresponsive controls

PCB faults can be difficult to diagnose without specialist testing equipment.

 

Residual Current Device (RCD) Sensitivity

Sometimes the dishwasher itself is not entirely at fault. Older or overly sensitive RCDs can trip more frequently, especially when commercial appliances naturally produce small levels of earth leakage during operation.

As multiple kitchen appliances contribute to cumulative leakage current, the protection device may trip even if no single appliance appears severely faulty.

This is particularly common in busy commercial kitchens with several high-powered machines operating together.

 

Poor Installation or Incorrect Power Supply

Incorrect installation remains a common issue in commercial kitchens. Problems may include:

• Incorrect voltage supply
• Undersized cabling
• Inadequate earthing
• Improper breaker ratings
• Shared circuits without sufficient capacity

Commercial dishwashers often have specific electrical requirements depending on whether they are single-phase or three-phase machines. If installation does not meet manufacturer specifications, recurring electrical faults are likely.

 

When To Call A Professional

You should contact a qualified engineer if:

• The dishwasher trips repeatedly
• There are burning smells or sparks
• Water leaks are visible
• Breakers trip immediately on startup
• The machine loses power mid-cycle consistently
• Staff are resetting breakers regularly

Electrical faults in commercial equipment should never be treated as DIY repairs. Professional diagnostics ensure the fault is identified safely and accurately.

 

You Might Find Useful:

• Our guide on Troubleshooting Tips For Your Commercial Dishwasher
• Our guide on Commonly Asked Commercial Dishwasher Questions

• Our guide on Cleaning Your Commercial Dishwasher