Mcb in consumer unit

[Baker1988]

Hi every one how are we all ob this loverly day?
i am currently doing my level 3 at college and i just wanted to ask sone thing i was gonna ask my tutor but i forgot. So here goes i have just moved in to a flat and i looked at the fuse board and it is a new board with mcbs and is rcd protected i was looking at the mcbs and they are aranged properly starting at 40 next to the main swich and going down all the way to 6 amp but then at the very end of the board next to the six amp there is a 40 amp mcb for my shower. I alway got told at college u had to arrange them from highest to lowest so the current has less distance to travel. But my question is is it just good practice to arange them highest to lowest or is it actually dangerous to arange them any other way? Will it actually make it electricaly unsafe?

 

[Dan the spark]

It's good practice to do it this way, your shower was probably added to your fuse board at a later date hence it being on the end. It won't be a problem

 

[Baker1988]

Thanks i was just curious thats all was not sure if it made the consumer unit unsafe of not as i did not want a fire to start or some thing

 

[telectrix]

it's usual to fit the highest load MCBs nearest to the main switch for a good reason. the higher the load, the higher the current, so the greater the flow of electrons. now, under a new european directive, hot from brussels by carrier pigeon, it's considered unsporting to make these poor little electrons travel further than they have to, hence a short run up and down the busbar is considered enough excercise for them. in the case of having the shower furthest from the main switch, the electrons may get over tired and make your shower run cold, leading to a massive incrfease in global warming.

enough of this frivolity, it's not a problem, as has previously been said.

 

[Octopus]

When doing CU changes the length of the "existing" cables often dictate the positions of the new MCB's, as I'd rather have not to extend cables where possible.

That said thats why clear marking of circuits is essential (see my thread "for newbies and trainees")