Safety Knights

Throwing Electrical Disconnects

May is National Electrical Safety Month, so each Wednesday this month, we're bringing you some tips and info related to electrical safety in (and out) of the workplace! ⚡

In today's post, we're going to take look at the "1-Hand Rule" that applies to "throwing" an electrical disconnect.

Whenever you need to "throw" a disconnect, where and how you position your body is critical! When performing this task, we want to avoid having any part of our body in the "line-of-fire" in case an arc flash were to occur. In order to do this, you follow the "1-Hand Rule" (previously called the "Left Hand Rule"), which includes the following steps:
• 𝐀𝐥𝐰𝐚𝐲𝐬 𝐬𝐭𝐚𝐧𝐝 𝐭𝐨 𝐭𝐡𝐞 𝐬𝐢𝐝𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐝𝐢𝐬𝐜𝐨𝐧𝐧𝐞𝐜𝐭 - 𝐧𝐞𝐯𝐞𝐫 𝐝𝐢𝐫𝐞𝐜𝐭𝐥𝐲 𝐢𝐧 𝐟𝐫𝐨𝐧𝐭 𝐨𝐟 𝐭𝐡𝐞 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭. If an arc flash occurs, this prevents you from being directly in the path of the intense thermal energy (up to 35,000°F, which is ~4x the temperature of the sun), flying schrapnel (which can travel up to 700 mph), and the pressure waves associated with it.
• 𝐈𝐟 𝐩𝐨𝐬𝐬𝐢𝐛𝐥𝐞, 𝐚𝐥𝐰𝐚𝐲𝐬 𝐬𝐭𝐚𝐧𝐝 𝐨𝐧 𝐭𝐡𝐞 𝐬𝐢𝐝𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭 𝐭𝐡𝐚𝐭 𝐰𝐢𝐥𝐥 𝐩𝐫𝐞𝐯𝐞𝐧𝐭 𝐲𝐨𝐮 𝐟𝐫𝐨𝐦 𝐡𝐚𝐯𝐢𝐧𝐠 𝐲𝐨𝐮𝐫 𝐚𝐫𝐦 𝐚𝐜𝐫𝐨𝐬𝐬 𝐭𝐡𝐞 𝐟𝐫𝐨𝐧𝐭 𝐨𝐟 𝐭𝐡𝐞 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭. If the lever is on the right side of the disconnect, stand on that same side and use your left hand to operate the equipment (as shown in the picture below). You don't want to risk having severe burns and/or broken bones from the arc flash. An arc flash can sometimes completely break the panel door off the hinges!
• 𝐓𝐮𝐫𝐧 𝐲𝐨𝐮𝐫 𝐡𝐞𝐚𝐝 𝐚𝐰𝐚𝐲 𝐟𝐫𝐨𝐦 𝐭𝐡𝐞 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭, 𝐜𝐥𝐨𝐬𝐞 𝐲𝐨𝐮𝐫 𝐞𝐲𝐞𝐬, 𝐭𝐚𝐤𝐞 𝐚 𝐝𝐞𝐞𝐩 𝐛𝐫𝐞𝐚𝐭𝐡, 𝐚𝐧𝐝 𝐡𝐨𝐥𝐝 𝐢𝐭. If an arc flash occurs, it will emit superheated gases. When a person is scared (like you would be if an arc flash occurred right in front of you), a common first reaction is to gasp, causing you to inhale. Inhaling these superheated gases, flames, vaporized copper, and other toxic chemicals can really do some damage to your lungs!
• 𝐅𝐢𝐧𝐚𝐥𝐥𝐲, 𝐲𝐨𝐮 𝐰𝐢𝐥𝐥 "𝐭𝐡𝐫𝐨𝐰" 𝐭𝐡𝐞 𝐝𝐢𝐬𝐜𝐨𝐧𝐧𝐞𝐜𝐭 𝐢𝐧 𝐚 𝐬𝐰𝐢𝐟𝐭, 𝐝𝐞𝐜𝐢𝐬𝐢𝐯𝐞 𝐦𝐨𝐯𝐞𝐦𝐞𝐧𝐭 𝐰𝐢𝐭𝐡 𝐧𝐨 𝐡𝐞𝐬𝐢𝐭𝐚𝐭𝐢𝐨𝐧.

Whenever you are performing this simple, yet common task, always ensure you're wearing the proper PPE based on a properly performed risk assessment.