Suggestions please

[electricAl]

Any thoughts/suggestions re: this job would be much appreciated, as farm installs aren`t my usual fare. I`ve agreed to help sort it as the farmer`s a bit desperate as he`s got the DNO booked to fit a new pole mounted tranny in not much more than a week!
The entire install is in desperate need of improvement, but like a lot of farmers, he`s put up with it for donkeys - `if it aint broke, don`t fix it`. Now he`s having to accept improvements have to be made - the catalyst being the new tx, brought on by the imminent completion of a new robot dairy.
The existing install consists of the present (40 yr old) dairy, large grainstore, workshops, garages, numerous livestock buildings with truly decrepid light fittings, & 2 domestic dwellings - back to back built (approx 8 beds between em) Most is typically farm bad.
Present TP 70kva supply is overhead to outbuilding loft, approx 80m run. The soon to be installed replacement is underground 140kva supply originating from same pole mount. As to be expected, DNO plan the install of new cut-outs & CT meter on ground floor of same outbuilding & the existing TT arrangement to continue.

Thus far few facts are established at present. As best as i can decypher, the new 24/7 automated dairy will consist of 4 robots, with apparently a 11kva load each + ancillary items such as compressors, brushes & office etc. I hope to have the actual figures verified Monday. Lighting the new 78m x 36m dairy structure is likely to require 24 HQI hi-bays at first guess. An accurate all encompassing load calculation hasn`t yet been done, but a 4c x 70mm SWA already purchased for the 145m sub-main run to new dairy. At least it`ll be big enough
Other than timescale, my immediate concerns are...
The DNO suggestion to farmer that the domestic supplies be incorporated into the new CT Metering - even tho the present arrangement is tap-offs via 3 overhead lines into house(s) & their seperate cutouts/metering (my supposition being the lowest overhead conductor would be `earthed` - so probably TN-C arrangement within the new install )
A 73kva diesel gen-set lives in the adjacent building to the intake

Altho its not been started or serviced for 3+years, farmer wants it incorporating in new arrangement, to avoid down time with his expensive new dairy. Not all that familiar with gen-sets, but doubt ATS or controls will be rated above 100a of original install & certainly not the 200a of new supply. So, with a max output of 100a anyway, it`ll only be able to provide back-up for the new dairy alone.
So, splitting the whole install close to origin would seem necessary, with the dairy the sole recipient of one half of the 200a supply, & everything else on the other. In light of my measuring >0.9a earth leakage for the whole farm, such an arrangement becomes even more attractive. The DNO will undoubtably want to see earth fault protection close up to his CT Meter (altho past experience tells me not to assume anything )
Even a slugged 500mA front ender would be set to spoil the cows milking fun me thinks.
Apologies for such a long post, but kind of a compicated brief. Idea`s to supplement my own gratefully received.

 

[Guest123]

Lot of info there mate......I'll have to digest a bit and offer some thoughts in a bit.

 

[malcolmsanford]

Lot of info there mate......I'll have to digest a bit and offer some thoughts in a bit.

Read this earlier Lenny and thought .........whew it's not a forum you need but a design consultancy. Not sure what advice can be given without actually walking the job and seeing for yourself

 

[Bigboy247]

Good post with lots of details, best I can do is break it down into bits and get as much information as possible this will give you a good starting point, 70mm swa 4c is a good starting point get as much information of every bit of kit that he wants and go from there. I would get the farmer to get the Gen serviced as three years is a long time to sit on a farm unused and could play up. Look at it as small parts not the whole, wood for the trees stuff. Well will have a good think on this one as did large stabbles a few years back on farms, but which ever way you plan it plan it well as it could bite you big time. Nice pictures at least the boards are still on the wall.When you get it all done and it looks nice the farmer will want to move all the equipement round and give you mind melt as what looks good on paper doesn`t always look good in life.

 

[Guest123]

Read this earlier Lenny and thought .........whew it's not a forum you need but a design consultancy. Not sure what advice can be given without actually walking the job and seeing for yourself

Quite true Malcolm.


Initial thoughts I had though are regarding the mains position.

I would probably install an MCCB panelboard (MEM for me) adjacent to the CT chamber, suitably sized for number of outgoing circuits and appropriate main incommer etc.

Install a number of earth electrodes to get your Ra/Ze down as low as possible, I mean sub 30ohms, this will enable you to use a higher rated earth leakage relay with associated shunt trip to cover your ADS as it's a TT and provide for better discrimination.

Reason I choose MEM is that I'm most familiar with they're range off MCCB's and additional bits and bobs to go with them, that make them do what ever you like protection wise via different settings etc.

Obviously 705 will have some guidance too with regard to protection & earthing of agri premesis etc.

As said geney needs a good going over, maybe even an overhaul and incorporating via changeover switch etc. Myabe even think about auto seqeuncing for start up immediately on mains failiure.

Loading needs cosideration, particularly on the geney....dont want to end up with a pile of molten metal do we.

 

[electricAl]

Thanks fella`s - appreciate it aint the easiest of situ`s to offer suggestions on.
The 70mm was actually purchased on advice from the `electrician` that was there before me (i suspect being able to use a cable calculator may have been his best qualification) Came about due to the farmer planning a 2nd, identical dairy close to the first - supposed timescale approx 5 years from now. Whilst the 70mm is fine for now, it could get interesting in the future!
Quite right about splitting the install into sections to form any kinda plan - too extensive not to. But of course, its all gotta tie together aswell.
Academic really, as its all gotta go, but the existing switchgear is a lesson in abject design...
Overhead supply attaches other side of cut-outs in first pic (tapped off before entry to feed overheads to houses)
Thru cut-outs (red got a bit warm at sometime me thinks) down trunking to meters & second set of cut-outs in room below, back up trunking to henleys, where it splits off to left to


...which seems to be serving a few lighting circuits & not much more these days.
Main feed comes out of henleys (all the following in single insulated tri-rated 25mm) thru floor to lower level, thru wall into adjacent gen-set & changeover switchgear, back into lower room, up thru floor & into Mem iso lower right of 1st pic of original post.
Exits (still in 25mm tri) into middle (silver) DB, splitting then off to left hand Mem, & also up to Old Bill (check out the seperate Neutral straight out of the Henley!)
Quality!
The left hand Mem feeds a 35year old 70mm that travels 130m to the grainstore, stopping on the way at a resin cable joint so it can slip into a more comfortable 25mm, before terminating into this

"what you mean, Merlin & crappy no-name TP breakers don`t fit Memshield boards - give it here, i`ll make it fit" & "course it`s adaquately protected under the eaves of the grainstore, its IP30"

Aswell as feeding the grainstore (metal clad 1363 s/o`s & IP30 DB inside) turns out the board also serves large industrial cement mixer (recent). More horrors re this DB later.

The old 3036 Bill appears to feed the remaining loads thru-out the farm, via that 16mm swa out to more shanty town overheads, ping ponging from one out-building to another before arriving at the old dairy, where i actually found the first token of earth fault protection in the whole place

Lucky it weren`t a ELCB...


Have a few more mugshots for later, but right now have to focus the ole grey cells on sortin the lighting out in the new dairy - if you have a mo to spare, please help to re-establish my sanity in this post

 

[pennywise]

This may be wrong but when a mate did a dairy farm last year he got Hager to design the distribution system and to spec the switchgear etc very much like a lighting manufacturer would design you a lighting scheme if you are going to be using there products.

 

[electricAl]

Sorry Lenny, missed your post before.
Agreed with the concept of panel board immediately downstream of origin, altho i was thinking Schneider meself - tho i do like Eaton`s stuff too. Had tried to consider all options inc. standalone insulated adjustable RCCB / busbar chamber / Quadbreak / MCB board /suddenly remembering i have to go on holiday next week & so on, but keep coming back to same concern - an amp or more of earth leakage whilst runnning just half the farm. Whilst that clearly needs addressing, time constraints are such i`m not confident they`ll be sorted adaquately in time - hence the requirement to split the load ASAP.
Panelboard can achieve that, but that takes me down the road of 500mA incomer, 300mA outgoing to satisfy both DNO`s & Bs7671 requirements - as i`m seeing it. Otherwise i`d be looking at adjustable type (very, very tempting!) With 100/30mA devices further downstream that also raises the question of discrimination...do i make the 500mA or 300mA S-type? and by rights at least one or other should be 4p, just to add to the spec requirement of 200a+. Thought how i could do without the RCCB incomer, use a vanilla switch disconnector instead, but that raises the spectre of earth fault protection lacking upto outgoing RCCB`s - don`t know of any double insulated, 200a rated panels
Already warned client the switchgear will have to be MCCB`s and thus pricy, so thats accepted (begrudgingly) but am attempting to keep this on the right side of silly money, but not too sucessful thus far...at the very least one MCCB panel at intake, additional switchgear other side of GenSet (assuming existing ATS can stay) + new switchgear in old dairy, IP rated DB outside new dairy, panelboard & contactors inside, as well as giving him the bad news his grainstore could blow up any minute
He`s gonna love me I`m sure he thought an MK Split Load Consumer would do it all.
Oh well...
Do appreciate your thoughts on it tho bud - starting to get that uncomfortable feelin` earlier

 

[Bigboy247]

Well whatever you do it can`t be any worst, nice drink for christmas at the end of it from the scrap man. Maybe a mess but it still worked sort of, ask the suppliers as said above on big jobs they might help you out with the spec worth a try.

 

[electricAl]

This may be wrong but when a mate did a dairy farm last year he got Hager to design the distribution system and to spec the switchgear etc very much like a lighting manufacturer would design you a lighting scheme if you are going to be using there products.

You`re not wrong atall. The thought had already struck me & i know a few who do this regularily.
Timescale is the killer here, but it may well be something i`ll investigate tomorrow.
Thanks.

 

[lewlec]

Hi

this sounds like it could be a nice job
i agree with lenny on the mccb panel board with a 500ma or 1amp time delay as an incommer using structural steel of the building as your earth, usually get a good reading off this.
Then feeding sub boards with 300ma td incommers being its an agricultural install. Also would feed each individual robot via 30ma rcd/rcbo because if a fault appears on 1 of these units you dont want too loose the others. As for lighting without seeing the set up its difficult to say but we normally use high frequency fluorescent fittings

hope this is of use
regards
gary

 

[Guest123]

Sorry Lenny, missed your post before.
Agreed with the concept of panel board immediately downstream of origin, altho i was thinking Schneider meself - tho i do like Eaton`s stuff too. Had tried to consider all options inc. standalone insulated adjustable RCCB / busbar chamber / Quadbreak / MCB board /suddenly remembering i have to go on holiday next week & so on, but keep coming back to same concern - an amp or more of earth leakage whilst runnning just half the farm. Whilst that clearly needs addressing, time constraints are such i`m not confident they`ll be sorted adaquately in time - hence the requirement to split the load ASAP.
Panelboard can achieve that, but that takes me down the road of 500mA incomer, 300mA outgoing to satisfy both DNO`s & Bs7671 requirements - as i`m seeing it. Otherwise i`d be looking at adjustable type (very, very tempting!) With 100/30mA devices further downstream that also raises the question of discrimination...do i make the 500mA or 300mA S-type? and by rights at least one or other should be 4p, just to add to the spec requirement of 200a+. Thought how i could do without the RCCB incomer, use a vanilla switch disconnector instead, but that raises the spectre of earth fault protection lacking upto outgoing RCCB`s - don`t know of any double insulated, 200a rated panels
Already warned client the switchgear will have to be MCCB`s and thus pricy, so thats accepted (begrudgingly) but am attempting to keep this on the right side of silly money, but not too sucessful thus far...at the very least one MCCB panel at intake, additional switchgear other side of GenSet (assuming existing ATS can stay) + new switchgear in old dairy, IP rated DB outside new dairy, panelboard & contactors inside, as well as giving him the bad news his grainstore could blow up any minute
He`s gonna love me I`m sure he thought an MK Split Load Consumer would do it all.
Oh well...
Do appreciate your thoughts on it tho bud - starting to get that uncomfortable feelin` earlier

Sounds like you could throw thousands at this one and still come up short......it's the biggest problem with most jobs......where do you stop??

Just try and break it all up....start at the start with main incommers first so as to get DNO on side and then a section at a time.

 

[nickblake]

i think the best way forward on this one is has been suggested , chose the switch gear you want to use and ring them direct and see if it can be designed for you , that way the head ach of the designe are off you back , but as time scale is the thing you could start but installing an i line board for the distribution and then work from their section at a time ,but like youve said ,farmers always have a new tractor but the electrics are well the ones ive seen are well scary

 

[mogga]

I was thinking exactly what Nick said Brand spanking 50K tractor Implaments and a luverly range rover along with the beat up defender and electrics from the arc expecting the electrical system to cope with the demands of a £100kstate of the atr robotic electronic thinggymajig wondering why it trips the fuse when used Bet he argues that you could put this here n that there n dont need that expensive bit of kit quoting Jimmy( another farmer) says You dont need all that stuff

 

[electricAl]

Thanks for all your thoughts fellas.
Have to admit i`ve drifted further & further from my original viewpoint of keeping the cost as low as poss - ultimately it`ll cost what it`ll cost, & dairy downtime could make these amounts look small if the job is compromised too much.
My first thoughts of protecting against nuisance tripping led me towards the Merlin Vigi adjustables, but explaining to the farmer the complexities & costs involved drew a predictable response...
So having exhausted pretty much all other avenues i`ve ended up full circle, back to an VELS at the origin.
Will tap up Scneider to see if `A man` can come out & quote, but am in little doubt thats where we`ll end up - stuff the cost. And Mogga, you`re a little way out with your guess mate - each robot costs more than that i`ve reckoned after a little checking this afternoon. And there`s 4 of em. Pity their aftersales tech guys give such little info away.

Gary, very interested in your usage of HF Fluorescents in preference over Hi/Low bays. Farmer had received a quote for 24 off IP56 LowBay style fluory`s each kitted out with 4 single enders rated 220w in total. Supply only cost was £6900+VAT which ended his interest. Same quantity of decent quality IP65 Hi Bays unlikely to top £2k, & to be fair he`s been told he`ll be paying the same for his 140kva supply whether he uses it all or not - be interested to verify this with EON.

As to the use of steel structure as earthing, its unfortunate that its not at source - yet to confirm the validity of main rod within GenSet building. Looks a bit better than the rod in my earlier post tho. But the steel structure of new dairy will have to be bonded, as with everything conductive within it, so will actually become the most effective earthing point in the whole install no doubt.

Will hopefully obtain some definate answers tomorrow, and will post back. Thanks to you all for your input.

 

[lewlec]

hi electricAl

just wondering how you getting on with this job?

regards
gary

 

[Knobhead]

Come on how goes it?

I’ve always done heavy industrial work (quarrying & steel) but I’ve been following this thread out of interest, so totally different to what I’m used to.

Having lived in a small farming community I know what they’re like, I’d get asked to do the odd “foreigner”. Usually I’d manage to wriggle out of doing them, but I got roped in a few times. My usual ploy would be give them a list of items required and the numbers of the wholesalers and leave them to haggle over the price. My fee was on top!

 

[DurhamSparky]

BBC News - Fire breaks out at dairy farm in Pikehall

(ignore the date) hahahaha!!


only kidding!!

 

[Knobhead]

Good job your in Durham otherwise I would get upset, you wouldn’t know about the hamlet of Pikehall in Derbyshire.

 

[DurhamSparky]

drove through it on my way to get some cable earlier in the year!