Please can I have a 30 amp supply?

[Lucien Nunes]

As you will see from my avatar flag, I have left the country of happy socket-outlets (Denmark) in favour of the East and I'm now in that last bastion of the good old British 5A plug... India. The widespread use of low-rated S/O's (they are typically rated 10A here) means that many small final circuits are of highly dubious CCC. Unfortunately my request for a 30A supply (or, two 15A supplies capable of being fully loaded at once) seems to have got lost in translation, resulting in a chap coming to tap one into a local final.

This is done at one of the ubiquitous grid assemblies with a dozen switches, a few fan speed controls and two S/O's . One feed to the lot, via 2.5 (black line, black neutral at the yellow tape joints) can't see which breaker supplies it. I vetoed that, so they have gone off to the market to get some 4mm² SWA to run back to the board. Looking forward to getting a hit of old-cable-colour-nostalgia. Although, I'm not 100% sure what they will return with....

 

[rapparee]

Out of interest.

What do you want to plug in.

 

[Lucien Nunes]

The main load is from a couple of 2.5kVA switched-mode power supplies and a couple of small 1-3ph (1/4 hp) motor inverters. The inrush on the PSUs is pretty hefty so I thought it better to get one 32A supply (30A in old money here) rather than two smaller ones, to stand the best chance of not tripping a B-type or type 2.

Well, they came up with the goods; they were soon back with a roll of 4c 4.0 XLPE SWA in glorious technicolour (but solid conductors, unlike trad UK SWA). This is now live from the main DB downstairs using red and black with the armour, or at least two strands of it, as CPC. I would have liked to get some mileage out of the extra cores - either doubled up to minimise the drop with the armour as earth or using the yellow core as earth, but given how efficiently the guys reacted to my request I didn't want to nit-pick. If there's any uncertainty about the CPC or Zs, I'll bolster the earth from another circuit. The SMPSUs do kick out plenty of leakage so it's worth getting a decent connection.

 

[Lucien Nunes]

We're in operation now although I haven't put full load on the supply yet. There was no point trying to find a gland, also half my tools and equipment were stuck in customs including useful things like jubilee clips and pipe, so I made off the earth by stripping back 6" of sheath, forming the armour into a bundle, plaiting a tail of flexible into it, then twisting it tight with pliers. It would stand any reasonable fault current. A European-style JB completes the termination.

The traditional 'test-lamp', consisting of a lampholder with a pair of leads, still thrives in India. Here is the local spark's one that was used to test the circuit:

 

[Pete999]

We're in operation now although I haven't put full load on the supply yet. There was no point trying to find a gland, also half my tools and equipment were stuck in customs including useful things like jubilee clips and pipe, so I made off the earth by stripping back 6" of sheath, forming the armour into a bundle, plaiting a tail of flexible into it, then twisting it tight with pliers. It would stand any reasonable fault current. A European-style JB completes the termination.

View attachment 52202

The traditional 'test-lamp', consisting of a lampholder with a pair of leads, still thrives in India. Here is the local spark's one that was used to test the circuit:View attachment 52201

Remember making them as an Apprentice, always used a Pigmy lamp though, less cumbersome, that was of course until my boss opened his Wallet snd bought us a John Drummond Tester each,

 

[marconi]

May we ask what you are doing in India?

 

[Lucien Nunes]

Working on a film project, doing something that is probably not being done anywhere else in the world at this moment - location 35mm & 70mm cine projection. It would be inappropriate to show too much of what we are doing due to NDA's etc. Projectionist is one of my other hats that I only wear now for very special projects, same deal as picking up electrical tools, TBH. I don't tour as often now as when I was in live audio production, I have too many ties to London and my family to be away much.

On this particular show, last Saturday I had the privilege to see inside a historic 1150-seat 1947 cinema in Mumbai, that still has a pair of carbon-arc equipped Bauer mechs in the beautifully conserved attached preview theatre. It's a wonderful place and the manager was enthusiastic and friendly and is really into the history. This I can and will post some pics of, there was a bit of vintage MEM switchgear etc. We fired up one of the old projectors and I was looking forward to running a show there, but our print did not arrive in time. I last ran an arc in front of an audience in 1996!

 

[marconi]

Lucien Nunes's exotic travels to far flung places make Wilko and mine's recent joint electrical project to increase the rate of production of chips - and thereby reduce the length of the queue - using 3 or 4 x 3kW electric fryers fed by an underground SWA 6mm2 single phase supply to a catering van at Borehamwood seem rather dull! But I bet Lucien has not had to do any Fermi estimates as Wilko did to arrive at the solution -