Surge Protec on Devices (SPD) and the 17th Edi on 1st Amendment of BS7671 Wiring Regula ons

Surge Protec on devices available from DEM Manufacturing (branded Roxburgh EMC) have for many years offered market leading pro‐

tec on from damage caused by high energy short dura on electrical transients. These are typically caused by nearby electrical storms

(atmospheric origins) or the switching of induc ve, capaci ve and resis ve loads (switching origin). Transients can cause a variety of

problems from equipment failure to serious electrical fires and damage to distribu on systems.

Surge Protec on Devices have historically not been covered by BS7671 Wiring Regula ons, despite the vital role they can play in pro‐

tec ng electrical and electronic equipment. However, this has now changed with the recently published first amendment implemented

1st January 2012.

BS7671 17th Edi on, Chapter 44 relates to protec on against Voltage Disturbances and Electromagne c Disturbances. Sec on 443

deals specifically with protec on against over‐voltages of atmospheric origin or due to switching. Details are given as to the types of

installa ons where the risk assessment will always lead to the result that SPD is required and other areas with lower levels of conse‐

quences where calcula ons can be used to determine the need for SPD installa on. See specifically 443.2.4.

Chapter 53 deals with protec on isola on, switching, control and monitoring with 534.2 determining specifically the selec on and

erec on of surge protec on devices. Two specific types of SPD are referred to in the regula ons as Type 2 and Type 1 dependant on

the nominal discharge currents expected and the loca on of the protec on within the system. DEM’s Surge Protec on Devices meet

BS EN 61643‐11 and DEM’s class B (DVSB series) meet Type 1 and DEM class C (DVSC series) Surge Protec on Devices meet Type 2

specifica ons as referred to in chapter 53.

BS7671 WIRING REGULATIONS

1st Amendment implemented 1st January 2012

 

KEY SECTIONS  Chapter  44  ‐  Voltage  disturbances and electromagne c disturbances   ‐  Sec on  443    Protec on  against over‐voltages  of  atmospheric  origin or due to switching  Chapter  53  ‐  Protec on,  Isola on, Switching, Control and Monitoring   ‐   Sec on 534.2   Selec on and erec on of surge protec on devices 

DEM Manufacturing, Deltron Emcon House, Hargreaves Way, Sawcliffe Industrial Park, Scunthorpe, North Lincolnshire. DN15 8RF

Tel: +44 (0) 1724 273200 Email: sales@dem‐uk.com www.dem‐uk.com/roxburgh

Contact our Technical Sales team on +44 (0) 1724 273216 

We will be happy to answer any ques ons or help with product selec on 

17th Edi on 1st Amendment Surge Protec on Devices

Roxburgh Item System Supply Appendix 16 Diagram Type1/Type2

DVSC400454TNS TT connec on Type 1 3 Phase + Neutral 16A2 Type 2

DVSC400454TT TT connec on Type 2 3 Phase + Neutral 16A3 Type 2

DVSC400453TNC IT 3 Phase 16A4 Type 2

DVSB400654TNS TN‐C‐S 3 Phase + Neutral 16A5 Type 1

DVSC400454TNS TN‐C‐S 3 Phase + Neutral 16A5 Type 2

DVSC275452TNS TN‐C‐S Single Phase 16A5 Type 2

I ProtectiveConductor

N

L3L2L1

6N

1

4a

4b

2

5

SPDSPDSPDSPD3

Distribution board1.Main earthing terminals or bar2.Surge protective devices ensuring a protection 3.level in accordance with overvoltage Category II Earthing connection of surge protective devices, 4.either 4a or 4b, whichever is the shorter routeCurrent-using equipment5.Residual current protective device (RCD)6.

OCPD 1: Overcurrent protective device at the origin of the installationOCPD 2: Overcurrent protective device

DVSC400454TNS Surge Protection Device recommended for use with TT systems, connection Type 1 (CT 1)SPD connected to the load side of an RCD according to regulation 534.2.5(i)

3 :

>125A gL

125A gLMin. recommendedcross section 6mm²

OCPD 2

OCPD 1

Last Update

04/04/2012

10/04/2012

DVSC400454TNS01

Tel No. +44(0)1724 273216 email: sales@dem-uk.com Website www.dem-uk.com

DEM Manufacturing, Deltron Emcon HouseHargreaves Way, Sawcliffe Ind. Park,

Scunthorpe, North Lincolnshire, DN15 8RF, UK ISSUE NUMBER

Part No:

I

ProtectiveConductor

N

L3L2

L1

6N

1

4a

4b

2

5

SPDSPDSPD3

Distribution board1.Main earthing terminals or bar2.Surge protective devices3.

Earthing connection of surge protective devices, 4.either 4a or 4b, whichever is the shorter routeCurrent-using equipment5.Residual current protective device (RCD) installed 6.downstream of the surge protective devices

OCPD 1: Overcurrent protective device at the origin of the installationOCPD 2: Overcurrent protective device

3:

>125A gL

125A gLMin. recommendedcross section 6mm²

OCPD 2

OCPD 1

3a

Surge Protection Device recommended for use with TT systems connection type 2 (CT2) SPD connected to the load side of an RCD according to regulation 534.2.5(ii)

3a. Surge protective devices (SPDs 3 and 3a in series ensuring a protection level in accordance with overvoltage Category II.

Last Update

10/04/2012

24/04/2012

DVSC400454TT01

Tel No. +44(0)1724 273216 email: sales@dem-uk.com Website www.dem-uk.com

DEM Manufacturing, Deltron Emcon HouseHargreaves Way, Sawcliffe Ind. Park,

Scunthorpe, North Lincolnshire, DN15 8RF, UK ISSUE NUMBER

Part No:

I ProtectiveConductor

L3L2L1

6

1

4a

4b

2

5

SPDSPDSPD3

Distribution board1.Main earthing terminals or bar2.Surge protective devices ensuring a protection level in 3.accordance with overvoltage Category II Earthing connection of surge protective devices, 4.either 4a or 4b, whichever is the shorter routeCurrent-using equipment5.Residual current protective device (RCD)6.

OCPD 1: Overcurrent protective device at the origin of the installationOCPD 2: Overcurrent protective device

>125A gL

125A gLMin. recommendedcross section 6mm²

OCPD 2

OCPD 1

z

Surge Protection Device recommended for use with IT systems

Last Update

10/04/2012

24/04/2012

DVSC400453TNC01

Tel No. +44(0)1724 273216 email: sales@dem-uk.com Website www.dem-uk.com

DEM Manufacturing, Deltron Emcon HouseHargreaves Way, Sawcliffe Ind. Park,

Scunthorpe, North Lincolnshire, DN15 8RF, UK ISSUE NUMBER

Part No:

Source See note 4

See note 5

SPB

SPB

SPB

SPB

SPB

SPB

SPB

SPB

SPB

SPB

Installation

OCPD 2OCPD 3

4

5

3

6

PEN

OCPD 1OCPD 4

919

2

87

L1

L2

L3

N

PE

Distributionboard1.Distributionoutlet2.Mainearthingterminalorbar3.Surgeprotectivedevice,DVSB400654TNS(Type1)4.Earthingconnection(earthingconductor)ofsurgeprotectivedevice5.fixedequipmenttobeprotected6.Surgeprotectivedevice,DVSC400454TNS(Type2)7.Surgeprotectivedevice,DVSC275452TNS(Type2orType3)8.Decouplingelementorlinelength9.

NOTE 1: for further information reference should be made to CLC/TS61643-12NOTE 2: SPDs 4 & 7 (or 7 & 8) can be combined in a single SPDNOTE 3: SPDs may require additional modes of protection for sensitive equipmentNOTE 4: BS EN 62305-4 covers the protection of electrical and electronic systems within structures against lightning.NOTE 5: Section 443 of BS 7671 deals with the protection of electrical installations against transient overvoltages of atmospheric origin, transmitted by the supply distribution system and against switching overvoltages generated by the equipment within the installation

Installation of types 1, 2 and 3 SPDs for example in TN-C-S systems

4 : 7 : 8:

Last Update

10/04/2012

24/04/2012

TN-C-S SYSTEMS01

Tel No. +44(0)1724 273216 email: sales@dem-uk.com Website www.dem-uk.com

DEM Manufacturing, Deltron Emcon HouseHargreaves Way, Sawcliffe Ind. Park,

Scunthorpe, North Lincolnshire, DN15 8RF, UK ISSUE NUMBER

Part No:

Part No:

ISSUE NUMBER

Tel No. +44(0)1724 273216 email: sales@dem-uk.com Website www.dem-uk.com

DEM Manufacturing, Deltron Emcon HouseHargreaves Way, Sawcliffe Ind. Park,

Scunthorpe, North Lincolnshire, DN15 8RF, UK 01

TN-C-S SYSTEMS