UK Am2 Breaker Selection

[CokeCanBrad]

Hi I want too do my AM2 In the future. I want too know the breaker selection for the circuits in the AM2, an acceptable answer (for me.) will be from a recent am2 Passee (successful candidates only.).
The circuits are as Follows:-

D.O.L Starter, with motor.

Carbon Monoxide Detector

Ring Final Circuit with a spur off to an additional outdoor socket this one will need additional protection RCD OR RCBO?.

16 amp TPNE Socket (Its the red 3 phase commando socket.)

2-way and Intermediate Lighting (I know 6 amp but rcd or b type or rcbo?.)

S- plan heating circuit with solar heating added too it.

Kind regards COKECANBRAD

 

[SparkyChick]

Just so you know... you get a wiring diagram that tells you exactly which breakers to use.

The installation part of the AM2 is a test of your ability to install to a design and in accordance with the regulations. It's all in the candidate guide which you should read thoroughly before starting each section.

 

[CokeCanBrad]

Just so you know... you get a wiring diagram that tells you exactly which breakers to use.

The installation part of the AM2 is a test of your ability to install to a design and in accordance with the regulations. It's all in the candidate guide which you should read thoroughly before starting each section.

Are you 100% sure on that? In the candidate checklist i went through the second thing on the composite installation was selection of protective devices, so how are you proving you know how to do that if they just tell you on a wiring diagram?

 

[SparkyChick]

I did my AM2 in December 2018. I didn't have to do any cable calculations, loading assessments etc. for the composite installation. I just read the diagrams.

But, lets just work through it logically using what you know to take an educated guess....

Smoke alarm... cable entirely on the surface, IIRC it has a fused spur on the supply and is wired in FP200. What OCPD rating would you use for this? What curve (B/C/D)? Does it need RCD protection?

Lighting circuit... What rating? Curve? Does it need RCD protection?

Work through each circuit like that and post your reasoning here and you'll get some feedback. And while you're at it, start a conversation with @Dan and apply to get access to the trainee only section... lots of useful info there

 

[CokeCanBrad]

I did my AM2 in December 2018. I didn't have to do any cable calculations, loading assessments etc. for the composite installation. I just read the diagrams.

But, lets just work through it logically using what you know to take an educated guess....

Smoke alarm... cable entirely on the surface, IIRC it has a fused spur on the supply and is wired in FP200. What OCPD rating would you use for this? What curve (B/C/D)? Does it need RCD protection?

Lighting circuit... What rating? Curve? Does it need RCD protection?

Work through each circuit like that and post your reasoning here and you'll get some feedback. And while you're at it, start a conversation with @Dan and apply to get access to the trainee only section... lots of useful info there

yeah i got a cheeky photo of the board its got a spur with a 3 amp fuse, its not a smoke its a hard wired CO Detector.
Also it wont let me onto dans account

and Im guessing it would be a 6 amp b type for that circuit

 

[SparkyChick]

Also it wont let me onto dans account

When you click that link, you should get Dan's (in case you don't know, Dan is the forum owner) profile popup. At the bottom of that there should be a button marked 'Start conversation'. Click it and you'll be starting a private conversation with Dan.

and Im guessing it would be a 6 amp b type for that circuit

You guess correctly. Work through the rest and when you give us your attempt, include a little of reasoning as to why you made the choice you did. This is the most helpful as it will help provide advice.

 

[CokeCanBrad]

When you click that link, you should get Dan's (in case you don't know, Dan is the forum owner) profile popup. At the bottom of that there should be a button marked 'Start conversation'. Click it and you'll be starting a private conversation with Dan.



You guess correctly. Work through the rest and when you give us your attempt, include a little of reasoning as to why you made the choice you did. This is the most helpful as it will help provide advice.

I know this because its what we use when we wire smoke circuits.

a quick google says an average CO Detector uses 1 amp ish.

1.5mm cable is rated for 14.5a in my blue book nice bit of headroom there

since that CO that uses 1amp ish is no where near that its acceptable to use a 6amp breaker

finally its a domestic setting so B- type is what we use, C is for commercial and D is for industrial

 

[SparkyChick]

Good logic

Apart from the last statement about breaker types which is, I'm sure you're aware, a huge simplification of selecting an appropriate tripping curve.

 

[Lister1987]

And while you're at it, start a conversation with @Dan and apply to get access to the trainee only section... lots of useful info there

That's my line! ?

 

[davesparks]

I know this because its what we use when we wire smoke circuits.

a quick google says an average CO Detector uses 1 amp ish.

1.5mm cable is rated for 14.5a in my blue book nice bit of headroom there

since that CO that uses 1amp ish is no where near that its acceptable to use a 6amp breaker

finally its a domestic setting so B- type is what we use, C is for commercial and D is for industrial

A CO detector will use nowhere near 1Amp, that would be an awful lot of power to operate a small amount of electronics.

If its less than 1A why not use a 1A MCB rather than a 6A?

No, B, C, D does not denote domestic, commercial, industrial, it denotes the tripping curve or how much inrush the MCB can tolerate be for tripping.

 

[CokeCanBrad]

No, B, C, D does not denote domestic, commercial, industrial, it denotes the tripping curve or how much inrush the MCB can tolerate be for tripping.
[/QUOTE]

Your right but then from my hands on experience i know that i use b types in houses (6 amps on my smoke circuits, give me a good example of you using a 1a MCB.), c types in the offices i refurb in london.

and d types in the plant rooms that run all the equipment for the building services

 

[davesparks]

No, B, C, D does not denote domestic, commercial, industrial, it denotes the tripping curve or how much inrush the MCB can tolerate be for tripping.

Your right but then from my hands on experience i know that i use b types in houses (6 amps on my smoke circuits, give me a good example of you using a 1a MCB.), c types in the offices i refurb in london.

and d types in the plant rooms that run all the equipment for the building services
[/QUOTE]

why do you need examples of a 1A MCB being used? I only asked why not use one, it was a question designed to get you to think about why you are selecting a 6A MCB.
I use 1A MCBs a lot to protect small control circuits, PSUs etc.

But why do you use those types of MCB in those situations. in my experience I have used both B and C in domestic and commercial installations.

 

[pc1966]

There are many cases when a 1A or 2A MCB would be a better choice, but quite a few CU brands have 6A as the smallest size and reg now make using another suppler's stuff a no-no.

 

[Ed Evans]

Hi I want too do my AM2 In the future. I want too know the breaker selection for the circuits in the AM2, an acceptable answer (for me.) will be from a recent am2 Passee (successful candidates only.).
The circuits are as Follows:-

D.O.L Starter, with motor.

Carbon Monoxide Detector

Ring Final Circuit with a spur off to an additional outdoor socket this one will need additional protection RCD OR RCBO?.

16 amp TPNE Socket (Its the red 3 phase commando socket.)

2-way and Intermediate Lighting (I know 6 amp but rcd or b type or rcbo?.)

S- plan heating circuit with solar heating added too it.

Kind regards COKECANBRAD

Have you done your AM2 yet as i used to be an assessor which means I have 99% of the answers from the horses mouth not guesses

 

[CokeCanBrad]

Have you done your AM2 yet as i used to be an assessor which means I have 99% of the answers from the horses mouth not guesses

Hi I havent done my AM2 yet so how can you help me?