Warehouse mains upgrade and generator

[sparky_1989]

Hi guys I have been tasked with upgrading some old rewireable fuseboards for a food warehouse that runs continually 24/7. I was asked to do an EICR on the install as there maintenance guys were having issues with blowing fuses. Wiring issues are sorted now. These fuse boards are old asbestos type fuses with client looking for Surge protection and RCD protection for circuits along with futureproofing for solar. I've attached some photos that show the setup which include

-3 x mains fuse boards

-4 x sub boards all fed from the multiple mains boards in photos

-Switch fuses controlling sub boards

Been an approved spark for over 15 years but looking on best way to do this without disrupting them as it's a bit of a logistics headache planning best way to tackle it while keeping power on for them . The food warehouse is open 6am -6pm. The warehouse runs multiple cold rooms 24/7 which is on its own dedicated modern RCBO consumer unit that is fed from 1 of the mains board that I'll be working on. As you can see from photos it will be tough getting matching consumer units like for like due to trunking etc there is only 14 circuits in use as most of these old boards were for previous owners work shop

Load wise is computers, random sockets throughout with very little plugged in (radios), small chargers for forklifts, led lighting throughout, 4 x 2kw heaters, heavy on the cold room side of things

My thinking was 1 or 2 new large consumer units with generators to feed the boards temporarily but not sure best way to do this (I've got a contact for sourcing big generators) Just wondering what guys that do these kind of works regularly for places that require constant power do in these situations. Would you throw in come CT meters which would help with th solar panels getting added in the future. I'll be doing the install as a 1 man band.
Thanks

 

[pc1966]

Other than computers without UPS, most stuff can be off for a few tens of minutes without problems to change over, but you might get surprises when doing so and finding out things are not quite as documented.

Have you got an overall specification for the installation? Total number of circuits, power ratings, overall average and peak demand?

While that looks quite a beefy set-up, it also looks rather like it is a 100A 3-phase meter so not too big. Having said that, you might want to use a MCCB board for distributing to all sub-boards just to get the good selectivity from most MCCB feeding MCB/RCBO. Not cheap, but easier for non-skilled folks to reset than to replace fuses in a handful of switch-fuses for the job.

As you already suggest, keep a few spare ways in every board.

Not sure if it is applicable where you are but having a meters at sub-boards, etc, to monitor consumption might be a requirement.

 

[SJD]

Rather than try to fit a new board in the space of an existing one, would it be more practical to install a new board to the right of the paler steel trunking, then move required circuits over to this new board?

You'd need to power everything down for a short while to connect the new board to the busbar chamber, but if all the cables were prepared that time might be quite short. Then you can move the required circuits over to the new board more leisurely, without disrupting the power to the switch fuses and whatever they feed.

Finally another brief power down to disconnnect the supply to the old boards.

 

[SparkySy]

I have fitted combine distribution boards in place of systems like you have here that have 8-12 3phase MCCB ways and the same with MCB's. They are very versatile and can be made to order.
I would do as above and try to site the new distribution to the right of the trunking where the newer switch fuse is, then identify and swap over the circuits.
This will minimize the time circuits are down and give you chance if required to provide a power alternative either a generator or power from another area that is not going to be affected.
Sy

 

[pc1966]

I have fitted combine distribution boards in place of systems like you have here that have 8-12 3phase MCCB ways and the same with MCB's. They are very versatile and can be made to order.

What make / model did you use? That sounds an ideal solution.

I have seen the Hager hybrid panels but they are normal MCB/RCBO and a few slots for 80-125A 1.5 module MCBs, not MCCBs.

 

[pc1966]

I would also suggest that the OP looks closely at the design, basically the end of cable Zs values already in use, to check that MCCB will be acceptable for disconnections times. Fuses are generally far more forgiving of higher Zs while still meeting the 5s sub-main or 0.4s final circuit times, and the margins in the current design might not be enough for simple MCCB (fixed, or just small adjustment to thermal point).

You can do it with fancy electronic MCCB where the short-term trip can be adjusted, and obviously very easy with those RCD features, but they get quite expensive!

 

[sparky_1989]

Some excellent advice here thanks. That hybrid combination board sounds exactly what I'm looking for. Any advice on brands that allow this setup if anyone has fitted similar.

 

[SparkySy]

The ones I used were Proteus, I know some people don't rate this switchgear but it all went together nicely and I have had no complaints or issues with it. The last was about 8 years ago for a leisure center.
The price was good and it was made as I requested within about 2 weeks!
All in all they were very helpful and protective devices are readily available for them without them having to come from Germany!
Sy

 

[ipf]

I like those handles on the old busbar chamber, by the way.

 

[pc1966]

The ones I used were Proteus, I know some people don't rate this switchgear but it all went together nicely and I have had no complaints or issues with it. The last was about 8 years ago for a leisure center.

Useful to know. A quick search of CEF finds this "standard" model but good to hear you can get variations made as needed:

12 Way 200A Triple Pole and Neutral MCCB Panelboard with 200A Switch Disconnector Incomer Fitted

Range of MCCB up to 160A SP and TP MC range terminal capacity 70mm sq

www.cef.co.uk

I am a bit surprised it is not more common as it seems such a handy option for the first / main DB that also has a good few final circuits, and the couple of MCCB in turn give you good selectivity with down-stream sub-boards, all the while your end circuits are on MCB or RCBO at sane prices (OK for up to 63A / 45A).

 

[SparkySy]

Yes that's the sort @pc1966 !
I actually remembered that I did one a couple of years ago on a farm that ended up split into commercial units! They made that one for me too as I had no height but plenty of width, so the MCCB's were left hand side MCB's on the right, that had 250a supply that was inline with the MCCB's to save space. It was a good design layout!
I too am surprised they are not more widely used although Proteus has a bit of a bad rep.
I can honestly say that I've never had an issue with their products, most of them were still compatible with older units. I have used them for a great many years now. Also they do reduced height DP RCBO's at a third of the cost of Hager, so for customers that don't want to take out a second mortgage it's a good option!