100A breaker?

[D Skelton]

So a conversation with a fellow spark brought into question what exactly are main switches?

Is a 100A main switch a 100A double pole MCB or does the 100A mean its breaking capacity? I'm sure it's the former but I'm beginning to question my own knowledge as he thought differently.

Also, with different rated RCDs, 25, 40, 63...etc, Does that mean that it will trip if the current passing through it exceeds that amount essentially acting as an RCBO? If so, why do we need RCDs to double up as overcurrent protective devices as well?

This is probably quite a basic question but the reason we wondered is because we all seem to fit CU's with 100A main switches even when the cut out fuse is only rated at 60A or 80A. If the main switch is indeed a 100A overcurrent protective device, why is this?

 

[Andy78]

I agree that some of the comments were harsh, but these are things that I would definately raise an eyebrow at if a self employed domestic installer said them to me. I would say some knuckling down and revision is a very good idea indeed. Every sparks should be aware that every item of electrical equipment has ratings of the voltages and current it is designed to carry. How can you use them properly if you don't ?

We are all learning every day however, no matter our experience. This forum is for questions to be asked and answered. I am a new member so don't know if this is the way round here, but a lot of people come in for abuse when asking for help. How helpful is that really ?

 

[Andy78]

D Skelton, just for some info, maybe interesting, maybe not. On 3 phase distribution boards you do get MCCB incomers, RCD incomers, and switch disconnectors that fit in the same board, although this will differ by brand. Domestic CUs main switches are just switch disconnectors however.

 

[D Skelton]

Erm it isnt About knowing everything , however knowing basics like that is a given

So yes if you didnt know that a main SWITCH is not a breaker you are in the wrong job pal, i take it your another one who doesnt have nvq level 3?

Jesus christ get real man, theres no wonder Electrical Trainee get away with it because the world is full of people like you, i can imagine an apprentice asking this sort of question and id gladly answer them, however not an APPROVED CONTRACTOR, boils my blood it really does, someone who signs off work saying its safe is asking whether or not the main switch is a breaker

Your on the same level

For the record, I'm no Electrical Trainee, but who are you to question the job I do and why on earth should I have to come on here and have justify myself to you?! I worked dam hard to qualify as an electrician, excelling above and beyond my fellow students at the time! I have gaps in my knowledge yes, I'll be the first to admit that, but I'm also sure I have knowledge in other areas of eletrical work that would far surpass yours. I guarantee that some of your gaps in knowledge would be what I would consider to be basic but I assure you that you wouldn't catch me on here shooting you down for asking a basic question.

You badger on about the importance of an NVQ and yet you only completed your 2391 last month where as I completed it years ago! A qualification that many regard as having much greater importance than the NVQ. Not that I proclaim to be an expert because of one poxy qualification!

I know that a 100A main switch is double pole, I know that it is rated to only carry 100A, I know that it is suitable to provide isolation, I know it is linked and I know when I do and don't need one. I also thought for a moment that it might have functioned as a breaker, whooptie doo!

If I'd never have asked, I'd never have known, and funnily enough, no one at college ever explained to me exactly what a main switch is. If this is such crucial knowledge, tell me why no one ever thought it neccessary to tell me whilst I was studying??? Probably because it doesn't matter in the grand scheme of things!

Although it's good to know for example exactly how an RCD works, why is it neccessary? As long as you know where the regs tell you to put one, and what type it should be then there's never going to be a problem is there.

You sir have not been helpful or informative in any way, you have not advised me or even made known a professional or useful opinion. You have written nothing but abuse, and for no reason at all?! My only question is what made you so insecure that you had to shoot down a fellow qualified electrician? Saying that, I don't even care, I have nothing more to say to you and I can proudly welcome you as the first member of my ignore list!

Finally, special thanks to Des and to all of you who have either educated me, informed me or even just stood in my corner. I salute you all

 

[D Skelton]

D Skelton, just for some info, maybe interesting, maybe not. On 3 phase distribution boards you do get MCCB incomers, RCD incomers, and switch disconnectors that fit in the same board, although this will differ by brand. Domestic CUs main switches are just switch disconnectors however.

Thank you Andy, I am aware of this

 

[Andy78]

Thank you Andy, I am aware of this

Lol no worries. Hope I haven't insulted you, just don't know what you know. Plenty of domestic installers have never worked on 3 phase.

 

[D Skelton]

Lol no worries. Hope I haven't insulted you, just don't know what you know. Plenty of domestic installers have never worked on 3 phase.

You haven't insulted me at all, you provided a useful and informative post. Whether I already knew it or not is irrelevant

And I'm not a DI as I carry out larger scale commercial work as well as domestic.

 

[vernam616]

Certainly not insecure hahaha, just sick of reading these idiotic posts from so called "electricians"

You have a 2391 cause you learnt to pass the exam, otherwise you would have had the knowledge to know that. It wasnt a overload device

I pride myself on my qualifications and how hard i worked to get where i am today, if only everyone was the same

Apologies if you have been insulted as thats not in my nature to insult purposly, just really sick of reading stupid things like this

 

[Guest55]

I assure you both that in my new line of work, whatever that may be, I'll be sure to remain ignorant.

I hear McDonalds are taking on burger flippers.
More arrogance by someone responsible for electrical safety in customers homes.
Idiot.

 

[Darkwood]

Biff55 - i suggest you actually contribute to this forum before shooting ppl down then we can see what exactly you think you know and your background, whos to say OP hasn't been working in other electrical areas and just re-newing himself or maybe he worked for a company with a boss like you who just shot him down at every opportunity knocking his self confidence, if you read his other threads and posts you'll find hes quite capable but just tidying up his knowledge here and there, yes he might have been told it at college but can you honestly say you recall every detail.

 

[D Skelton]

I hear McDonalds are taking on burger flippers.
More arrogance by someone responsible for electrical safety in customers homes.
Idiot.

Oooh hello! Hopefully you'll get banned for that remark but just in case, welcome to the second slot on my ignore list

Good day

 

[Spudnik]

Two members have now received a temporary ban.

If anyone else would like to join them, please let me know.