Lightning and Surge protection in commercial and industrial installations
Following on from my previous post on 21st November about Lightning protection in domestic installations we move on today to discuss lightning and surge protection in commercial and industrial installations.
BS7671 states that Surge Protection Devices (SPD’s) must be installed where the consequence of an over-voltage could result in an interruption of commercial and industrial activity, which in most commercial / industrial installations will be the majority of distribution boards.
When considering which device to install, we need to look at where on the electrical supply you are working. If you are working on a main incoming panel, you will need to assess whether the building needs a combined lightning and surge device (Type 1+2+3) to protect against direct lightning strikes. As discussed in the previous article, only buildings which are either fed by an overhead power line or have an external Lightning Protection System (LPS) will need a Type 1+2+3 device, otherwise a Type 2 device is sufficient. If you are working on a sub distribution board that doesn’t feed any external circuits, the device you will need is a Type 2, which will protect against any transient over-voltages.
If you were looking at protecting a whole commercial or industrial installation, rather than just the board you are working on, firstly a device will need to be installed on the main incomer, then any sub distribution boards more than 10 meters away will need their own protection. Unfortunately, surge protection has a limited range of protection, which is limited after a 10 meter radius, and as surges are most often caused inside the electrical installation rather than transmitted from the main incomer, it is important to ensure that the devices are installed as close to the equipment you wish to protect as possible.
If you want to discuss this any further please call our specialist surge team on 01484 851 747.