Protect Your Sensitive Equipment From Lightening & Electrical Surges
Always do you best to protect sensitive automation and control hardware from lightening and other forms of electrical discharge. Highly delicate sensors do not need much of a surge to render them completely useless. Constantly servicing and replacing damaged sensors is extremely expensive and could potentially put lives in danger if on a critical system or in a dangerous area.
The best course of action is to implement electrical surge protection in the design phase of the project. However, sometimes that just doesn't happen and now you have to add protection to critical systems and sensors after fabrication and installation. There are many ways to protect from electrical discharge but keep in mind that if there is a way, electricity will find it. Its difficult to get 100% protection but anything is better than nothing.
The most obvious protection is a lightening rod. Ensuring a proper and adequate grounding method from rod to earth is critical. ACI installed this rod on top of a flood retarding structure in central Texas to try and protect the extensometer we were constantly replacing. They had installed a rod on the other side of the structure @ the SCADA panel but that did nothing for this side. After consulting with the customer, we decided it was best to use the railing as the conductor to ground. At the end of the railing, a couple hundred yards away, we attached a ground rod, following proper installation procedures. After this rod was installed we have not had to replace that instrument since.
Another method is to use surge protection terminal blocks. These make installation simple and quick. One thing to keep in mind about these is that they may not work with every sensor so pay close attention to the wire diagram and the sensor specs. They are also expensive, sometimes costing $30 or more per terminal block!
This device is an in-line surge protection device for a single instrument. the cable from the instrument side terminates into this box before finally terminating at the designated location in the control panel. This in conjunction with the lightening rod mentioned previously gives us extra protection from electrical discharge and surges. This method is also easy to implement into existing systems and is cost effective.
Being proactive in protecting your critical systems and sensors will payoff in the end by increasing service life and decreasing unplanned down time. Potentially saving thousands, if not millions of dollars, and possibly someone's life.