Extra arc flash protection: the maintenance switch

Your electrical panels can do more than control and distribute. With the right components, just about anything becomes possible. In this section, we focus each time on one such component in a cabinet. This time : the maintenance switch. An additional measure as arc flash protection

An electric arc or arc flash costs lives. The explosion of heat leads to severe or even fatal burns. Servicemanager Bart Van Herck: “That is why it is so important to respect the safety regulations during maintenance work.”

But you can also opt for additional arc protection in the board itself. “With modern switches, you can largely reduce the set time delay for switching off. This reduces the energy released as well as the impact of the arc flash.”

Second parameter set

How does this work?

By equipping the circuit breaker with a so-called maintenance switch. When turned over by the technician, he or she activates a second parameter set in the main switch.

Thanks to that set, the switch will turn off faster in the event of a fault and a possible arc. To activate that maintenance switch, the technician needs a special key.

Several manufacturers offer this arc flash protection device. The names are different, but the principle always boils down to the same thing. Schneider Electric calls it the ERMS function, which stands for Energy Reduction Maintenance Switch. At Siemens, it’s called DAS, the Dynamic Arc-Flash Sentry. ABB’s modern Emax switches are also equipped with this technology.

“Especially customers with critical buildings are asking for this functionality: hospitals, data centers and industry. Environments with regular maintenance work that cannot take place de-energized. For example testings within the context of power quality or thermography.”

“But since safety comes first for everyone, it is obviously a worthwhile investment for every project. Especially since the additional cost is limited.”

Arc flash protection: also for existing boards?

“We can also equip certain existing switches with such a maintenance switch. Some hardware modifications in the cabinet and then surface-mount or flush-mount the switch near the main switch. But whether that is technically feasible depends on switch to switch.”