4 Core - Zone / Sounders

[Mozcom]

Hope someone can help - have looked in BS but found nothing.

Recently asked to quote for an upgrade.  Dated Photain Panel - 2 zone

4 Core used for each of the 2 Zones but only 3 cores used
2 cores for + - of Zone and 1 core for Positive of Sounder cct - Negative from Zone cct commoned across to negative of sounder ccts.

Is this right / conforms?

As I'm up against some large corperate org. competing for the upgrade who service these premises (bearing in mind that it's a solicitors premises and I need some concrete evidence), can this FP cable be jointed out to accomadate some extra 40 devices as they have no AFD and comply.

There is no evidence is there quote to suggest that they will loop the 2 EOL's to install an adressable system.

Sounders are obviously not on there own cct.

They have no intention of puting in a new panel in with a One man test function.

Need a bit of clarification if any one can help please.

Thanks

[Benzerari]

Sounds like 'Three Wire System'

There are number of issues that need to be taken into acount in such kind of install, I will try to remember and get back to you, I remember one of the HAES product can be wired as 'Three Wire System'

[Galeon]

If it’s wired in mineral there is a good chance it’s a 3 wire, no detection is also a give away, and I think the panel has been modified to run this old job.
You don’t say whether the end of lines are monitored , so your wiring could be teed and spurred , don’t assume that an end of line is a monitored radial.
If it not a 3 wire, it might be a conversion to a hybrid semi monitored system, years ago we would have a 24v feed to each detector and a reference core.
They obviously know something that you don’t, and who says they are going to comply, do yourself a favour and unless you know without a doubt how this building is wired etc, quote correctly to cover you, there is no point in carrying on with this unless you have an eggs for eggs specification.
Remember Salesmen who get it wrong , leave it to the fitters , commissioning guys , they can afford to lose money , so you might as well go to the cash point and give your proposed client some money now.

[Benzerari]

Two important things:

1.   The number of detectors that can be supported by three wire system is considerably reduced compared to the number of a normal conventional system with the zones entirely separate from the sounder circuits.

Therefore you need to calculate the max load the system can support, due to the negative wire will have to support the excess of current drawn in fire condition, 40 extra detectors I am really not sure… need calculation

2.   The Diode of the base has to be fitted in the right direction and in the positive wire… if my memory still intact, also this neutral common wire should also be of enough low impedance because it carries all the current for the sounders and detectors.

[Galeon]

This might help , I am going back some time , I am sure that you will be unable to get the LED to activate on a detector which is installed on a 3 wire system , there was a time when you couldnt get a detector to work at all .

[Allen Higginson]

They may be going to upgrade the panel to one of the two wire variants and install sounder bases with the detectors, ditch the bells and utilize two of the existing cores for the field wiring.
Bit of a heath robinson but would possibly bring it up to spec if wiring sound and good.

[Benzerari]

Hope someone can help - have looked in BS but found nothing.

Recently asked to quote for an upgrade.  Dated Photain Panel - 2 zone

4 Core used for each of the 2 Zones but only 3 cores used
2 cores for + - of Zone and 1 core for Positive of Sounder cct - Negative from Zone cct commoned across to negative of sounder ccts.

Is this right / conforms?

As I'm up against some large corperate org. competing for the upgrade who service these premises (bearing in mind that it's a solicitors premises and I need some concrete evidence), can this FP cable be jointed out to accomadate some extra 40 devices as they have no AFD and comply.

There is no evidence is there quote to suggest that they will loop the 2 EOL's to install an adressable system.

Sounders are obviously not on there own cct.

They have no intention of puting in a new panel in with a One man test function.

Need a bit of clarification if any one can help please.

Thanks

My major suggestion is that you need a 'Full and Accurate Survey' to get the required details of the system to be able to bit your competitor and get upgrade purchase

If you are not sure, just get rid of it!

Upgrading a bike to a motor bike it does not need only a motor... does it?

[Galeon]

They may be going to upgrade the panel to one of the two wire variants and install sounder bases with the detectors, ditch the bells and utilize two of the existing cores for the field wiring.
Bit of a heath robinson but would possibly bring it up to spec if wiring sound and good.

BEWARE THE TEE'S & SPURS

[Allen Higginson]

They may be going to upgrade the panel to one of the two wire variants and install sounder bases with the detectors, ditch the bells and utilize two of the existing cores for the field wiring.
Bit of a heath robinson but would possibly bring it up to spec if wiring sound and good.

BEWARE THE TEE'S & SPURS

...hence "if wiring sound and good"!!

[Galeon]

They may be going to upgrade the panel to one of the two wire variants and install sounder bases with the detectors, ditch the bells and utilize two of the existing cores for the field wiring.
Bit of a heath robinson but would possibly bring it up to spec if wiring sound and good.

BEWARE THE TEE'S & SPURS

...hence "if wiring sound and good"!!

Comment made in jest , as stay off the moors and on the road !

[Allen Higginson]

BEWARE THE TEE'S & SPURS

...hence "if wiring sound and good"!!

Comment made in jest , as stay off the moors and on the road !

Ahhh,the good old Slaughtered Lamb.

[Benzerari]

They may be going to upgrade the panel to one of the two wire variants and install sounder bases with the detectors, ditch the bells and utilize two of the existing cores for the field wiring.
Bit of a heath robinson but would possibly bring it up to spec if wiring sound and good.

Good cost effective idea Buzz! but needs panel change as well!

[Allen Higginson]

They may be going to upgrade the panel to one of the two wire variants and install sounder bases with the detectors, ditch the bells and utilize two of the existing cores for the field wiring.
Bit of a heath robinson but would possibly bring it up to spec if wiring sound and good.

Good cost effective idea Buzz! but needs panel change as well!

They need to be pricing it pretty tight not to be able to allow for a two wire conventional!!

[Wiz]

Hope someone can help - have looked in BS but found nothing.

Recently asked to quote for an upgrade.  Dated Photain Panel - 2 zone

4 Core used for each of the 2 Zones but only 3 cores used
2 cores for + - of Zone and 1 core for Positive of Sounder cct - Negative from Zone cct commoned across to negative of sounder ccts.

Is this right / conforms?

I thought the original question was 'do 3-wire systems comply with the current recommendations of BS5839 Part 1 2002?'

Clause 12.2.2.a states ' A fault on one circuit containing manual call points, fire detectors or fire alarm devices, or a combination of them, should not affect any other circuit.

The definition of a 'circuit' in BS is 'Assembly of fire alarm components supplied from the same control equipment and protected against overcurrents by the same protective device(s) or current limitation arrangements.

Most 3 wire systems I have seen rely on a 'common' wire shared on the zone and alarm circuits and overcurrent protection on each of the other two 'legs'.

Surely, therefore, a fault on the 'common' wire could be deemed as a fault affecting two circuits.

Any comments from other residents of this home for the slightly bewildered?

[Galeon]

A solicitors , with no money ?