crs brochure - issue19-online - Page 12



SURGE PROTECTION DEVICES
THE CRS PRODUCT GUIDE
18th New Regulations – Surge Protection Devices
18th Edition Wiring Regulation
The introduction of the 18th Wiring Regulations BS7671
were released on a draft in July 2018 and will come into
force on the 1st January 2019.
There have been two major areas of interest within this
publication: 1) The introduction of Surge Protection devices
in domestic installations (SPD); 2) Arc Fault Detection
Devices in domestic installations (AFDD).
The two major product related changes for the 18th
edition wiring regulations are listed below:
Currently SPD devices are installed if written into the
installation specifications or if the installation is
deemed to be a high risk area, e.g. high rise buildings,
overhead cables etc., and normally only at the intake
position of the building, not at secondary distribution
points, but things are about to change...
The installer now has to carry out a localised risk
assessment of the property and its electrical supply, this
exercise will determine if the SPD is a requirement or not.
The risk assessment is based upon the properties
geographical location, the amount of lightning flashes
per year and how the incoming electrical supply enters
the building. All of these factors have an outcome which
determines if an SPD is a requirement.
SPD’s have now been introduced as a mandatory
requirement into the 18th edition wiring regulations
for domestic installations.
z T he introduction of SPD (surge protection device)
as a requirement based on the risk assessment criteria
for domestic installations.
Order Code
Description
CUSPD1110
SPD Type 1 & 2 2 module TT and TNCS295.66
z T he recommended use of AFDD (arc fault detection
device) in certain areas of domestic/commercial
& industrial buildings.
CUSPDT21
SPD Type 2, 1 module 60.00
CUSPDA01
CUSPDA01 SPD Accessory cable stacking kit each8.75
START:
Lightning
protection system
installed to BS EN
62305
YES
Each
NO
YES
Overhead supply?
Type 1 SPD
NO
ADDITIONALLY
YES
CUSPD1110
Sub
Distribution
boards >10m cable
distance away?
Risk
Assess*
Human life?
Public service?
Industry
activity?
NO
YES
Type 2 SPDs
YES
Risk
Assess
Groups of individuals?
Individuals?
ADDITIONALLY
CUSPD2070
NO
Sensitive
electronic
equipment?
YES
YES
Type 3 Surge
Extension Leads
4GAS
NO
Surge
protection required
as part of
AQ value or risk
calculation?
* According to BS 7671 (443.2.4 note 2), there is no need to perform a risk assessment calculation for levels
of consequence, because this calculation always leads to the result that protection is required.
Note :- Within section 534 there is the 10m rule, about the voltage protection level of an SPD. E.g. if there was an SPD in the consumer unit, after this point the SPD has an effective
protection distance of up to 10m as defined in the BS7671 amendment 1, this means that a PC in a study >10m from the main SPD will need local over voltage protection.
This can be provided by standard surge protection extension leads – see current range in the catalogue.
12
ORDER NOW from CRS – Basingstoke 01256 297900





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