Welding Plugs and Receptacles

 

Change-out Welding Equipment 50% Faster with Reduced Arc Flash Hazard

 

Workers risk exposure to arc flash when disconnecting standard welding plugs and receptacles. To prevent accidents install UL/CSA switch-rated welder plugs and receptacles from MELTRIC. They are a combination plug, receptacle and disconnect switch in one device. MELTRIC’s receptacles/connectors feature a built-in switching function that ensures the contacts are safely deenergized before the welding machine plug can be withdrawn. Arc flash safety is ensured.

 

Switch-Rated Welding Plugs & Receptacles

 

 

CASE STUDY

 

MELTRIC Switch-Rated Plugs & Receptacles Provide Increased Flexibility and Efficiency to Edison Welding Institute

 

The Edison Welding Institute (EWI) provides expert assistance, research, consulting and training in the field of materials joining. Members include aerospace, automotive, government, energy and chemical, heavy manufacturing, medical and electronics industries.

 

Problem

EWI’s assignments require the constant rearrangement of 100+ workspace layouts and equipment. Andy Joseph, manager of Welding and Testing Labs, says, ”We have nearly every one of the recognized welding processes commonly used today, and they all require electricity. The equipment for all these different procedures takes space, but we’re not using them all at the same time, so we need to be able to change them out.”

 

Fused disconnects were attached directly to the overhead bus bars, with pin-and-sleeve connectors at the workstations. Safety was a concern because the disconnects were located at the ceiling level. Joseph explains, “We had to use a 20-foot pole with a hook on the end to turn off the power to a plug. Disconnecting live would have been an unsafe option.” From a safety standpoint, he adds, there was no way to disconnect quickly if someone was getting hurt.

 

Plant Layout

EWI’s 40,000 sq. ft. high-bay laboratory has three 1,600 amp bus bars providing 480 volt power throughout the facility, with more than 100 separate power drops for welding power supplies.

 

Alternatives Considered

EWI first considered installing disconnect switches at ground level for each location. This still would have required the pin-and-sleeve plugs to connect the equipment, and the switch boxes would have taken up valuable space. Joseph notes, “With 120 of the old connectors, we would have had to buy 120 disconnect boxes that would have required extra wiring.”

 

Solution Chosen

Instead, Joseph selected MELTRIC’s Switch-Rated plugs and receptacles. Pressing a push button off-switch on the MELTRIC receptacle breaks the circuit and ejects the plug to its rest position. Then the plug can be withdrawn from the receptacle in complete safety, since the circuit is already dead. When the plug and receptacle are separated, deenergization can be visually verified, and a safety shutter on the receptacle prevents access to live contacts.

 

Field Results

Protection from arc flash hazards was the key factor in the decision to use the switch-rated plugs and receptacles. An additional benefit, according to Joseph, is simplified compliance to the NFPA 70E Standard for Employee Workplaces.

 

He says, “With the disconnects overhead, we would have had to suit up with PPE (personal protective equipment) because there was no way to verify that the power was disconnected without someone going up in a manlift. Having the disconnect switch right in the plug eliminates the need for an arc flash hazard assessment or suiting up.”

 

MELTRIC devices also provide greater speed and flexibility. Joseph points out, “We have a limited amount of space and are continually changing out equipment for different projects. When we start or finish a project, we can pull out one setup and bring in another quickly and safely.” Joseph explains, “We may have to move one technology into another area, and the MELTRIC devices make that very simple.”

 

Another benefit, according to Joseph, is the easier installation of the switch-rated connectors compared to the previous pin-and-sleeve connectors. He says the MELTRIC devices offered a relative cost savings because of the inconvenience of installing the former connectors. “They required soldering,” he notes, “and we are constantly swapping equipment in and out. Changing the MELTRIC plugs and receptacles is a timesaver by comparison.”

 

EWI also uses MELTRIC devices on auxiliary equipment such as hoists, wire feeders, fume extractors, welding positioners, robotics, and travel carriages. Joseph says he purchased 20 each of MELTRIC’s 20 amp and 30 amp devices for these applications, all rated for 480 volt operation.

 

In summary, Joseph states, “Probably the biggest benefit for us has come from efficiency improvements. Previously, because of the difficulty with making disconnects during a changeover, we would leave workstations set up because it was hard to take them apart and put them back together. This made floor space hard to come by. It also caused some turf wars on how space was being used.

 

Now, changeouts are easier to accomplish, we have a more presentable area, and the engineers and technicians don’t have to worry about someone else tearing down their workstation because it is easy to set up again.”

 

The switch-rated devices used at EWI were provided through MELTRIC distributor Johnson Electric Supply, of Columbus.