MCB selection

[volta1]

Hi guys

i have a designer that has asked for 16amp type c MCB`s for all lighting ccts.even though in most cases the design load will be less than 10amp.surely a 10amp type c would be best.what regulation would help me prove this./

thank in advance for any posts

 

[topquark]

What cable are you using (type/size)?

 

[i=p/u]

maybe for extra lights in future

 

[malcolmsanford]

I just wonder if the designer as privy to some information that is not available to you.

I have to be honest if the designer was advocating a smaller device and I felt it was not capable of duty, I would question it. If though he as sized the load, selected a suitable size cable for the protection device then this is the designers choice.

Perhaps the fittings he as chosen as a high in-rush of current and he believes after looking at the technical spec that perhaps the 10amp MCB would be prone to tripping espicially as the device aged, so a 16amp would be the way to go.

 

[Deleted member 9648]

The device should be meet the requirements of 433.1.1.......if a 16a type C does then it will comply.
However if individual luminaires are not internally fused I would be looking at whether a 16a device will provide adequate protection.
There is also the issue of Zs, a max of 1.15 (80% rule of thumb)...for a 16a/C may be difficult to meet on some lighting circuits.

 

[davelerave]

the C type is commonly used on comm/ind with discharge lighting


maybe that's the way the circuits have been designed

'in most cases the design load will be less than 10amp'