Surge Protection

[Poult12]

Found this a March 2014 Professional Electrician and Installer Mag.
Might be of some help or good read.

 

[Poult12]

This may be more clearer to read

 

[Poult12]

Hope this is helpful for some people.

 

[Marvo]

Thanks Kieran. I have a question if I may.

Why does BS7671 contain regulations about surge arrestors?

Surge arrestors as outlined in the article above are installed with the sole intention of protecting items that don't form part of the electrical installation. BS 7671 is the code or regulations whose scope covers the actual electrical installation, not things that are plugged into it by the user so why does BS7671 even concern itself with surge arrestors at all when they're not designed or installed to protect the wiring or the socket outlets?

 

[Poult12]

In all honesty - not a clue.
I just seen this article and thought it might be of some use (to an idiot like me) and to other guys who are studying.

 

[Marvo]

I'm sure it will be appreciated and don't worry about my question, I'm just thinking out loud

 

[Sintra]

Extract from bs7671

Chapter 53 Protection, isolation, switching, control and monitoring, now includes a new Section 534 which
deals with the installation of surge protective devices (SPD). The requirements of Section 534 are for the
selection and erection of SPDs for electrical installations of buildings in order to limit transient overvoltages of
atmospheric origin transmitted via the supply distribution system and against switching overvoltages. The
requirements are also intended to protect against transient overvoltages caused by direct lightning strikes or
lightning strikes in the vicinity of buildings protected by a lightning protection system. The requirements do not
take into account surge protective components, which may be incorporated in the appliances connected to the
installation.

 

[Marvo]

Okay, I'm feeling a bit stupid. So the SPD regs in 7671 only apply to Type 1 surge protection which would be designed and installed solely to protect the actual electrical installation and not to any Type 2 or Type 3 devices which would protect electronic appliances against damage by transient overvoltage that's not a hazard to the installation?

 

[Sintra]

Other upstream systems might require additional type 2 spd's like life safety systems and critical hospital equipment etc.