Sprinkler Pump Supplies

[JameZZZ]

Hi,

I have a question about dedicated sprinkler supplies if anyone has any experience with them.

Here is the set up.

DNO's Three phase heavy duty cut out with 200A fuses. 95mm2 XLPE single core tails in galv trunking to the incomer on a 200A MCCB panel board.

A sprinkler system is to be installed and the sprinkler specialist has specified that the pump supply must come from the live side of the main switch (without any form of switching). How is this normally achieved?

I was thinking of having a busbar chamber before the MCCB panel with a switch fuse out to the main panel and then a separate switch fuse to the sprinkler supply (locked in the on position) but somehow I don't think the DNO will like meter tails going directly onto a busbar.

Does anyone have any practical experience with this requirement

Regards,

JameZZZ

 

[tazz]

There is a lot involved here, so would suggest getting full confirmation of install before starting.
Supply is usually bolted direct to incoming busbar, with the idea of running the pumps to self destruction. Isolation must be approved lockoff. Supply cables need to be run externally from the building were possible, and maybe required to be encased in contrete internally. Suggest searching for LPCB fire sprinkler systems for more info.

Try http://www.redbooklive.com/pdf/LPS1237_1_0_Electric_pump_controllers.pdf
Hopefully will be a starting point to help

 

[JameZZZ]

Thanks Tazz, I rang the NIC in the end. They said I should place a switch fuse within close proximity to the main incomer and size the cable to the switch fuse (utilising back fusing). The problem is that the sprinkler specialist is unhappy with any switching at all, even if it is locked on. However they don't offer any alternative solutions so they are going to have to lump it I think.

Regards,

JameZZZ

 

[guest119]

Are you sure of your amperage set up?
IE 200a incomer and 200a mccb.
I ask because the dno dont want call outs so your side would normally be less than theirs so if you are to have a 200a mccb they may insist on you winding it down to maybe 0.8%. Or, fitting a switchfuse before your panel fused at 150A.

 

[JameZZZ]

Hi Boydy,

I have had this potential issue before and they don't seem to bothered about discrimination with their cut outs. I suppose it depends on the DNO?

Regards,

JameZZZ

 

[Engineer54]

As Tazz has indicated Fire pumps come with their own set of rules. The very last thing you want in the supply line to a fire pump is a set of fuses, or other form of overload protection!! That fire pump delivering water to the sprinkler systems can be all that stands in the way of the whole building going up in flames and being totally destroyed...

 

[Knobhead]

^^^ What they said ^^^

Oh Dear the building going up in flames and the pumps have tripped out.
Sod the motors, so long as they keep going who cares what happens to them.

Stuff the NIC as usual they’re talking out of their arses.

 

[dingledong]

Thanks Tony ! !

 

[shanky887614]

surely this is ccommon sence

very expensive building being destroyed in fire or a couple expendable pumps burning out

how about a fuse from the mains to the fire pumps, but throw the fuse away and put a bar in there (the kind the dno use in flats)

 

[JameZZZ]

I understand what you area saying. However It would be nice to have some written guidance on the matter if am going to deviate from BS7671. With this in mind, I have contacted the Fire Protection Association who produce the LPC documentation. The document Which gives guidance in this area is TB 210:2008 Automatic sprinkler pump installation. Apparently it has schematics within it showing typical supply arrangements. They only produce hard copies and its on its way.

 

[Bobster]

Pretty sure there is a bit in the Bgb about this subject. Regarding motor protection.

 

[netblindpaul]

You would NOT be deviating from BS7671 if you omitted all protection for a fire pump circuit.
Tony & E54 are correct.
Oh, what a surprise, NOT.
Look in the BGB and all will become apparent.
Once again the NICEIC don't seem to understand the regulations.
Oh what a surprise, NOT!

 

[tazz]

This is a serious subject, with no room for guessing or IEE BS books......the op has taken the correct idea of seeking advice. As stated there are so many regs for the supply, I could fill the forum.......Load must sufficient to withstand pump seizure of 75% or complete stall, ensuring the pump windings are destroyed to open circuit, isolation must be engaged in off position when control panel is open...it is endless and a specialist project

 

[netblindpaul]

tazz,
I think that Tony, E54 & myself have basically agreed with you.
BS7671 whilst relevant is also irrelevant.
Also it seems that the NICEIC, again have no clue about what is needed.
Suprised, moi, non!

 

[tazz]

The NICIEE know were they can go....lol.... BSI, BAFE and LPCB worked very hard on this one, and other areas of high raised buildings. It took over 20 years of studying fires to come up with a separate exempt standard....if we followed NICIEE we would end up fitting 30mA rcds