Electrical safety boost at asphalt plant

At FM Conway, a member of MPA, its Electrical Engineering Team has been investigating improving safety and process efficiency across one of its asphalt plants in in the UK 

Location and staffing can compound the length of time a process is down, due to the size of sites and number of qualified personal available. Organising an approved electrician to be where they are needed when a reset is required is time consuming. Then there is the fact, most absence of voltage tests and reset procedures take up to 20 minutes at the enclosures, whether that be, transformers, control panels or switchgear panels, allowing downtime to become a serious productivity problem.

The FM Conway’s Electrical Engineering Team understood that the solution must allow a qualified, non-electrician to reset panels in total safety. This would require a contained automatic test procedure unlike the conventional processes that were being used.

The company worked with its panel builder contractor, EMEX control systems, to develop a solution that would meet different panel requirements across the site. The search highlighted a number of devices that indicated the presence of voltage but did not measure the absence of voltage via a test method. Expanding their search, they were introduced to the Panduit VeriSafe, Absence of Voltage Testers, through TLA electrical distribution. 

VeriSafe minimises the risk of electrical hazards by confirming the control cabinet is voltage-free before access. Compared to other portable test instruments, plant operators and machine builders can check whether an electrically safe environment is present much faster, safer, smarter, and more efficiently. 

VeriSafe automatically ensures that the entire test process is followed for every single test. With a push of a button, a qualified, non-electrician can achieve tested safety in both 3-phase and 1-phase applications in the extended voltage range up to 1000 V for AC and DC applications. The fail-safe design uses active indicators for plant status and complies with SIL 3 (IEC 61508-1) safety functions. 

According to the NEC, specified in NFPA 70E, an electrically safe environment must be ensured before working with electrical installations without voltage, and the measurement procedure is precisely defined.

Working with EMEX, FM Conway has combined the absence of voltage device (VeriSafe) with a door interlock system.  Jonathon Read, Electrical Engineering Manager, Aggregate and Asphalt, FM Conway commented, “As an additional safety feature the door will not open unless the test has been carried out successfully. The devices come with a set of safety contacts rated to SIL 3, and we worked with functional safety engineers to design a system which also conforms to SIL 3, to physically prevent anyone accessing the panel unless the test has been successfully carried out.” 

The FM Conway-EMEX design includes magnetically coded switches on the doors linked to the undervoltage coil on the main isolator, this guarantees that when the doors are open the system cannot be re-energized.

VeriSafe 2.0 is ideal for 480/600V CAT IV applications including outdoor, service access and all power distribution equipment including frequency converters and remote motor disconnect switches. VeriSafe 2.0 increases the possibilities to protect the entire electrical area, and if desired, it can be easily integrated into control systems via redundant semiconductor signal outputs (SIL 3). In addition, a network module for real-time diagnostics and performance reports is available. Thus, test results can be recorded with time stamps or data logs, or it can also be used for remote troubleshooting, monitoring the status of sensor lines as well as battery life or temperature development. Via the EtherNet/IP and Modbus TCP connection, for example, VeriSafe 2.0 can be easily integrated into Scada systems, or the integrated web interface can be used.

EMEX found that the test system can be easily mounted and integrated into EMC-compliant superstructures. Ensuring plant manufacturers can guarantee their design and compliance with standards, electrical safety, fire protection and mechanical safety. 

The trial of the system at the FM Conway asphalt plant has been successful and the Electrical Engineering Team and EMEX are planning fabrication of up to 45-panels with the VeriSafe absence of voltage system integral to the installation, across the site.  Mr. Read, summing up stated, “The VeriSafe solution is robust and simple to use absence of voltage test that has demonstrated its value in faster reset times and greatly reduced need for qualified electricians to undertake relatively simple tasks, allowing them to concentrate on activities that require their wider knowledge.”

As a member company of MPA, FM Conway entered the Absence of Voltage solution into the group’s MPA Annual Health and & Safety Awards 2022, where it won the Safer Maintenance and Housekeeping Category. 

www.panduit.com/VeriSafe