MEPworx Wiring – Protection requirements for SPD provision revised

by David Wren

In BS 7671:2018 Amendment 2, new regulation 443.4.1, greatly simplifies the circumstances and calculation checks that call for the provision of Over Voltage Protection or Surge Protective Devices (SPDs).
As detailed below.

Protection against transient overvoltages is required to be provided where the consequence caused by the overvoltage could result in:

• Serious injury to, or loss of, human life.
• Failure of a safety service.
• Significant financial loss.
• Significant data loss.

Those revised requirements can be selected in the Over Voltage tab of the Edit General dialog box.

Additionally, if a building has a Lightning Protection System (LPS), an SPD is specifically required on the Main Supply Cable. Failure to select an SPD, (or the correct type & rating of SPD) will result in an Error Message being displayed on the supply cable after performing a calculation.