Electrical installation certificate questions

[new sparky]

On an electrical installation certificate it asks for the main switch type. What are the Bs numbers and what are the main types for domestic use? It also asks for the prospective fault current. What would this be in a domestic installation? I would be very grateful for any help. Thanks.

 

[Big_Spark]

All that information is actually written on the Main switch, and the Type and BS number will vary with the unit installed, and the Fault current will vary with the type as well.

The Main Switch of an Installtion can be a Double Pole Isolator, a Triple Pole Isolator, a TP&N Isolator, a Double Pole RCD, a Double Pole DC sensing RCD, a Double Pole Time Delayed RCD, a Double Pole DC Sensing Time Delayed RCD, a Variable Trip RCD, or one of the three phase varients of the afor mentioned RCD's, not to mention Moulded Case Circuit Breakers (MCCB's) which come in single phase and three phase and in about four different types.

All the above have different BS numbers and fault characteristics. This information MUST LEGALLY be printed on the Unit casing, however the BS numbers for the various tyes are listed in the Regs book.

 

[new sparky]

Thanks FWL. The bit on the certificate about prospective fault current has a note saying 'by measurement or by enquiry'. To who do I enquire and what is it likely to be? I have some notes which say it should be the greater of either the short-circuit current or the earth fault current. Please can anyone tell me what short-circuit current and earth fault current is and how it can be worked out. Thank you.

 

[Big_Spark]

If you look at the device for the information, then that is "By Enquiry".

Without wishing to damage feelings, I do wonder if your even competent to be undertaling Testing and filling out the forms if you do not understand the Basics fo filling it in.

Personally I would suggest that you book yourself on a C&G2391 Course before you do any testing so that

• 1: You Know how to fill the certificates in Correctly
  
  2: You know where to find all relevent information
  
  3: YOu know how to carry out the tests safely as there are inherent dangers to testing installaions that you need to be aware of.

 

[new sparky]

Just doing an assignment at college mate (FWL). Appreciate the help anyway.

 

[new sparky]

If replacing a fuse board for a new consumer unit but supplier has not provided an isolater, what is the procedure? Do you need to cut the seals or do you work on it live? If you cut the seals are you putting yourself at risk of being sued? Thanks for the help.

 

[plugwash]

in theory you are supposed to ask the rec/dno

in practice many just cut the seals anyway and i've never heared of anyone getting in serious trouble for it.

some sparkys i know have even been given bags of seals by the rec guys