supply for marquee

[kme]

Okay.

Customer has a large (ish) pub, and has set aside an area to the rear for marquees (large weddings, fetes etc.)

He wants us to provide a supply they can put in the marquee to run bar, lighting, musicians equip etc.

Not a problem, per se, but here is the thought process / query.

The pub is TPN, PME. So I have to provide a local earth. The only way I can guarantee a good one is to put a rod down, with an inspection pit or similar.

They`re going to have a portable dist board, with a commando lead to connect to the premises. I`ll have to also provide a removable lead for the rod; BUT need to ensure that is connected before supply energises.

My thought at the moment is to fit some form of 3 pin plug / socket, and use the other two pins as a fixed link at the rod end, and a contactor supply at the DB, so the coil won`t energise unless the earth rod cable is connected.

Any thoughts greatly appreciated.

KME

 

[sparkytim]

Why not Rod down at the supply point on the Outside of the Building then this will be Permanant to the TPN Socket.

 

[septiclecky]

Okay.Customer has a large (ish) pub, and has set aside an area to the rear for marquees (large weddings, fetes etc.)

He wants us to provide a supply they can put in the marquee to run bar, lighting, musicians equip etc.

Not a problem, per se, but here is the thought process / query.

The pub is TPN, PME. So I have to provide a local earth. The only way I can guarantee a good one is to put a rod down, with an inspection pit or similar.

They`re going to have a portable dist board, with a commando lead to connect to the premises. I`ll have to also provide a removable lead for the rod; BUT need to ensure that is connected before supply energises.

My thought at the moment is to fit some form of 3 pin plug / socket, and use the other two pins as a fixed link at the rod end, and a contactor supply at the DB, so the coil won`t energise unless the earth rod cable is connected.

Any thoughts greatly appreciated.

KME

Have a look in Part 7 Section 740 think that might apply

 

[Lee321]

Why not Rod down at the supply point on the Outside of the Building then this will be Permanant to the TPN Socket.

thats the same as exporting. ie the ground closest to the socket could be at different potential especially assuming its some distance

 

[Lee321]

contactor and supply at pub

 

[kme]

That`s roughly the idea, Lee.

Back in a bit - off for tea........

 

[sparkytim]

thats the same as exporting. ie the ground closest to the socket could be at different potential especially assuming its some distance

Not sure what you mean but I was not suggesting exporting the PME earth but segregating it at the Supply point so the external installation then becomes TT (I take it that the RCD is installed to protect the supply cable)

The earth stake can be placed at the supply point just like any Caravan Site Pitch supply. Length of supply Flex and distance from Marque not relevent to TT earthing arrangement

See also arrangements for Marinas BRB Pg 195 Fig 709.1

Note Earth Rod at Supply end connected by Flexible cable to sockets

 

[Lee321]

tim it sounded as if you wanted to put your rod in next to the pub and the earth for the marque going up the outgoing cable to the marque at the pub end! yes or no?

if yes then your exporting no?

tim lets work on an assumption the marque supply is 40m from the pub

the cable would not need rcd at pub end using an earthed at one end only swa but an rcd will be needed somewhere

 

[sparkytim]

Yes Rod at Supply end

If you re-read Post 1 you will see the OP is going to feed Marque with COMMANDO LEAD AND PLUG not SWA from a SOCKET at the Pub end.

It will depend where the RCD will be installed, but I would be surprised if he was NOT going to protect the FLEX going from the Socket at the PUB to the Marque.

In which case the earth ROD NEEDS TO BE AT THE SUPPLY END.

NO EXPORTING OR INPORTING INVOLVED

 

[kme]

Right - lets see if I can help or confuse things some more.........

We`re going to need supplies for bar equip, lights and possibly musicians equipment, so I intend to supply all three phases.

I`d prefer to have 3 X SP breakers; so 1 overload doesn`t take out all circuits.

The reason I don`t want the 30mA at the commando socket by the pub is that, if a piece of bar equip, or a musicians amp has a fault, we`d lose all power, and someone would have to go from the marquee to the main building to re-energise.

I`m thinking 100mA(T) at the building (if required) ; protect the outgoing flex with the PME. Drop the earth at the portable DB, and have a seperate plug/socket to connect to the (permanent) rod. The DB could then be fitted with RCBos (thanks Sidewinder ) and everybods is happy??

Does that make things easier? I haven`t perused the BRB yet - thats tomorrow`s project.

KME

 

[steptoe]

by Jove I think lostit has it very well.

can I ask why the rod cant be permanently connected?

just wondering about getting a socket capable of carrying the PFC.

 

[kme]

If the marquee is only going to be there occasionally,

Then so is the portable DB.

So I have nothing to permanently connect the earth rod to.

 

[steptoe]

If the marquee is only going to be there occasionally,Then so is the portable DB.

So I have nothing to permanently connect the earth rod to.

AAHHHH,

so you are going to rod at the remote DB in the marquee (?), with a multicore flex(carrying the 3ph as well) back to the commando socket where you will have something to plug the coil wiring into?

or am I just talking total TAT.?

 

[NozSpark]

Why not stick something like a caravan supply box permanently somewhere close to where they want the Marquee and rod that???

 

[steptoe]

or simply have the flex feed into the coil beside the temp DB.

/yes, that sounds more sensible to me/

 

[kme]

Why not stick something like a caravan supply box permanently somewhere close to where they want the Marquee and rod that???

That is my other plan of attack - though it could be difficult to ensure it is correctly positioned for any size of tent!

or simply have the flex feed into the coil beside the temp DB./yes, that sounds more sensible to me/

Yes, mate. Thinking originally of the contactor attached/within the portable DB, and only providing power when the "earth cable" had been connected, IYSWIM?

 

[steptoe]

That is my other plan of attack - though it could be difficult to ensure it is correctly positioned for any size of tent!Yes, mate. Thinking originally of the contactor attached/within the portable DB, and only providing power when the "earth cable" had been connected, IYSWIM?

I do, that was my second thought, the first one was a bit idiotic TBH. :C

could we assume you are using armoured flex(?) then I see no reason not to do this,

the only problem I can see is policing the earth connection, 10mm getting moved about a lot, where do you put the cable when not in use etc... I assume you are going to have a permanent connection at the rod, otherwise you wouldnt know if it was connected properly each time.

or as Nozspark suggested

is there no nearby wall/fence you could place another commando plug/socket combination on and earth this permanently, then run your extension lead to this point(PME earth stops here), then run your lead(with rod earth) from here to your portable DB, best of both perhaps, permanent earth point and still the flexibility to move the tent size around.

 

[Andy™]

may be worth having a look at BS7909

 

[Lee321]

like this maybe?

 

[kme]

Lee - That was my original thought...

Andy - que 7909??? mate

Albert - Thanks.