Domestic

[Peter Woodford]

Guys

don't have my big read book handy at mo can you answer the following

1. 32amp circuit were protective measure against electric shock is ads is the maximum disconnection time permitted by bs 7671 = 0.5s

2. maximum Zs permitted by bs7671 for a 32amp circuit

3. What is the bs(en) for a rcd domestic


cheers

 

[acvc]

Q1. Don;t understand the question!

Q2. Depends on type of protective device.

Q3.

BS 3036 Rewireable Fuses
BS 1361 Cartridge Fuses (Consumer Unit Type)
BS 1363 Plug Top Fuses
BS 88 Cartridge Fuses (General purpose)
BS EN 60898 Miniature Circuit Breakers
BS 3871 Miniature Circuit Breaker (Old Style)
BS EN 60947 3 Main Isolators
BS EN 61008 Main RCDs
BS EN 61009 1 RCB0s
BS 7288 RCD Sockets
BS 1363 13A Plug Tops

 

[Peter Woodford]

acvc

Q1. is the maximum disconnection time on a domestic circuit type B 0.5 seconds

Q 2. BS EN 60898 Miniature Circuit Breaker

 

[acvc]

Q1. 0.4 sec for circuits up to 32A on TN systems.
Q2. 1.15ohms (temp adjusted i.e. 80% of values in BS7671).

 

[cbw]

32amp and above is 5.0 secs, 0.4 for anything below
Max Zs for type b 32 amp is 1.16 ohm.........already adjusted to 80%of 7671

 

[slocm3105]

32amp and above is 5.0 secs, 0.4 for anything below
Max Zs for type b 32 amp is 1.16 ohm.........already adjusted to 80%of 7671

Let me correct you slightly...

All final circuits rated 32A or under - disconnection time of 0.4s.
All distribution circuits and all final circuits OVER 32A - disconnection time of 5s.

And as stated above Max Zs for a tybe b MCB rated at 32A is 1.16 ohms(already with the 0.8 correction factor calculated).

Hope this makes things clearer for you

Cheers

 

[cbw]

Yep....your right!!!!......SORRY!!!

 

[slocm3105]

I know I am hehe . Tis always good to refresh our memories on this stuff though .

 

[cbw]

Was accused of being old fashioned yesterday!

 

[slocm3105]

Maybe you are .

Get the brasso out and polish up those ornaments

 

[cbw]

I have a well thumbed copy of the 14th edition sat in front of me, hence I know all about disconection times!

 

[Peter Woodford]

On my niceic dic booket is shows Zs at 32amps is 1.15 on a type b is this right or is it 1.16

 

[robsparky1975]

Guys

don't have my big read book handy at mo can you answer the following

1. 32amp circuit were protective measure against electric shock is ads is the maximum disconnection time permitted by bs 7671 = 0.5s

2. maximum Zs permitted by bs7671 for a 32amp circuit

3. What is the bs(en) for a rcd domestic


cheers

1. dis time 0.4s
2.zs max 1.44 ohms
3.bsen 61009

 

[Guest123]

Hi.

A main RCD is 61008, an RCBO is 61009.