Junction Boxes – Load Cell Summing & Connection Enclosures for Weighing Systems
Our junction boxes are specialist electrical enclosures designed for use in weighing systems, providing a secure, protected connection point for load cell cables in multi-cell platform scales, tank weighing systems, silo installations, and process weighing applications. By summing the signals from multiple load cells into a single output to the weight indicator, they are a critical component in any multi-load-cell weighing system — and their quality directly affects the accuracy, stability, and long-term reliability of the complete installation.
Unlike general-purpose electrical junction boxes, weighing system junction boxes include precision trimming potentiometers or digital trimming circuits that allow individual load cell signals to be balanced, ensuring equal contribution from each cell and compensating for minor variations in load cell sensitivity. This trimming capability is essential for achieving accurate, repeatable results from multi-cell systems. Our range includes standard industrial junction boxes for general weighing applications and ATEX-certified summing boxes for hazardous area installations in Zone 1, Zone 2, Zone 21, and Zone 22 environments. IP65, IP67, and IP69K-rated enclosures are available for outdoor, washdown, and harsh industrial environments.
Key Features
- Load cell signal summing for multi-cell platform, floor, tank, and silo weighing systems
- Precision trimming potentiometers or digital trimming for load cell signal balancing and corner correction
- IP65, IP67, and IP69K-rated enclosures for outdoor, washdown, and harsh industrial environments
- Stainless steel and GRP construction options for corrosion resistance in chemical and food environments
- ATEX-certified models available for Zone 1, Zone 2, Zone 21, and Zone 22 hazardous areas
- Multiple load cell inputs — 4, 6, and 8-way configurations for different platform and vessel layouts
- Cable glands and terminal blocks for secure, weatherproof cable entry and connection
- Surge and lightning protection options for outdoor and exposed installations
Common Applications
- Platform and floor scales — summing 4 or more load cells into a single indicator signal
- Tank and vessel weighing — multi-cell signal summing for accurate vessel weight measurement
- Silo and hopper weighing — load cell connection and summing for bulk material monitoring
- Conveyor weighing — load cell connection enclosures for in-motion weighing systems
- Outdoor weighing installations — weatherproof enclosures for exposed platform and axle weighing
- Hazardous area weighing — ATEX-certified summing boxes for Zone 1 and Zone 2 installations
All junction boxes are sourced from leading manufacturers and are compatible with standard mV/V load cells. Contact our technical team for advice on selecting the right junction box for your load cell configuration, environment, and installation requirements.
Frequently Asked Questions
What does a junction box do in a weighing system?
In a multi-load-cell weighing system, each load cell produces a small electrical signal proportional to the load it carries. The junction box connects all load cell cables, sums their signals into a single combined output, and sends this to the weight indicator. It also includes trimming adjustments to balance the individual cell signals, ensuring each cell contributes equally to the total weight reading regardless of minor sensitivity differences between cells.
What is load cell trimming and why is it important?
Load cell trimming (also called corner correction or span adjustment) is the process of adjusting the contribution of each individual load cell signal within the junction box so that all cells contribute equally to the total weight reading. Without trimming, a load placed in one corner of a platform may read differently to the same load placed in another corner. Proper trimming ensures consistent, accurate readings regardless of where the load is positioned on the platform.
How many load cell inputs do I need?
This depends on your platform or vessel design. Most platform scales use 4 load cells (one at each corner), requiring a 4-way junction box. Larger platforms or irregularly shaped vessels may use 6 or 8 load cells. Silo and tank installations vary depending on the number of support legs. Contact our team with your platform dimensions and load cell count for guidance on the correct junction box configuration.
Do I need an ATEX-certified junction box for hazardous area installations?
Yes. In a classified hazardous area, all electrical components within the zone — including junction boxes, cable glands, and interconnecting cables — must carry the appropriate ATEX certification. We supply ATEX-certified summing junction boxes for Zone 1, Zone 2, Zone 21, and Zone 22 installations. Contact our team to confirm the correct zone classification and certification for your application.
Can junction boxes be used outdoors?
Yes. Our IP65 and IP67-rated junction boxes are designed for outdoor use, providing protection against dust ingress and water jets or immersion. For exposed coastal or highly corrosive environments, stainless steel or GRP enclosures are recommended. Surge and lightning protection options are available for outdoor installations in exposed locations.
