Smoke alarm wiring circuit

[Tony59]

Hello. I am upgrading some AICO smoke alarms in a HMO where the existing alarms will expire soon. They are each wired from individual ceiling lights. On the top floor there are 4 alarms. I plan to go into the loft and from above, power the 4 top floor alarms from a single ceiling rose, instead of having each smoke alarm being powered from individual ceiling roses. I plan to use 6243Y (3 core + earth) cable that will allow me to interlink them and reduce the need for wireless signalling. So only one of the alarms on the top floor will require a wireless signalling module to communicate with the alarms downstairs.
My question is, "Should I wire them in series (one after the other) or can I have all 4 of them connecting to a common junction box."
I am asking, because it can be awkward to get 4+4 = 8 wires into the terminals of a single smoke alarm with your head pressed against the ceiling when wiring them in series. The junction box option could be easier for me.
I have included a diagram to help illustrate the 2 options that I am aware of.
Many thanks for reading this.

 

[Murdochcat]

Series

 

[EFLImpudence]

Are you sure?

The diagrams aren't much good without showing the individual wires.

 

[Tony59]

From the ceiling rose, the cable will be 2 core + earth.
Series option: Between each alarm will be 3 core + earth.
Junction box option: Between common junction box and alarms will be 3 core + earth.
The 3rd core will be for hard wiring the signal.

I have seen the series way being used before, but I wondered if it is acceptable to wire the alarms from a common junction box instead.
Thanks

 

[EFLImpudence]

This is parallel and series wiring:

 

[Tony59]

I should have probably described the 1st option as 'radial'. In effect both options are types of 'Parallel' going by what is taught at school, since live and neutral are connected to each device. I doubt that text book 'Series' is ever used in real life.
Anyway, what I want to know is should the alarms be wired consecutively, or can they be wired from a common junction box.

 

[Murdochcat]

Are you sure?

The diagrams aren't much good without showing the individual wires.

Yes. My understanding is that the op is suggesting spider or in series - but NOT like your drawing which is unhelpful to say the very least

 

[EFLImpudence]

Anyway, what I want to know is should the alarms be wired consecutively, or can they be wired from a common junction box.

It doesn't matter.

Both are connections in parallel.

 

[EFLImpudence]

My understanding is that the op is suggesting spider or in series

I would call it star rather than spider but neither is in series.

- but NOT like your drawing which is unhelpful to say the very least

On the contrary.

 

[Murdochcat]

I should have probably described the 1st option as 'radial'. In effect both options are types of 'Parallel' going by what is taught at school, since live and neutral are connected to each device. I doubt that text book 'Series' is ever used in real life.
Anyway, what I want to know is should the alarms be wired consecutively, or can they be wired from a common junction box.

I knew what you were getting at - others think they are being clever