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Old 22nd Apr 2018, 5:19 pm   #21
gramophone1
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Default Re: Daisy Chain Mains Extensions

What is branching ?

I have not come across that before ?
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Old 22nd Apr 2018, 5:54 pm   #22
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Default Re: Daisy Chain Mains Extensions

Example:

4 4way extensions plugged into a 4 way extension is branching, 5 4 way extensions plugged 1st one into the wall, 2nd on into the 1st and so on is daisy chaining.

Actually no. of ways doesn't matter for daisy chaining but you can only branch if there's more than one!
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Old 22nd Apr 2018, 6:10 pm   #23
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Default Re: Daisy Chain Mains Extensions

Thank you for that.
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Old 22nd Apr 2018, 6:18 pm   #24
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Default Re: Daisy Chain Mains Extensions

I don't think there is anything plugged into one of the (few enough, and nowhere near where needed) wall sockets in my house that isn't an extension lead! And there are more extension leads plugged into them ..... and even them, sometimes .....

For computer and audio / video equipment with only modest current consumption, cascaded extension leads are very unlikely to be a problem. Especially with the UK's system of every socket being earthed and every plug fused. Just make sure to plug anything over a kilowatt into the nearest one to the wall. The second-level extension leads can be fused at 5A or even 3A, limiting loading to 1150 or 690W respectively and hopefully blowing only their own fuses in the event of a fault.It's all about

If you stay within the wattage limits (3kW through a 13A fuse) and use only decent quality extension leads made with 1.5mm² flex, you will be fine.
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Old 22nd Apr 2018, 7:06 pm   #25
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Default Re: Daisy Chain Mains Extensions

Thank you

If I could find an unwired mains extension with more than six sockets would be ideal. The ones I use are pro elec,

Does anyone know if there are any of these available with more than six sockets ?
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Old 22nd Apr 2018, 7:20 pm   #26
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Default Re: Daisy Chain Mains Extensions

Didn't a firm called Olsen in London make metal distribution strips with lots of MK sockets. Used to advertise in WW

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Old 22nd Apr 2018, 7:41 pm   #27
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Default Re: Daisy Chain Mains Extensions

Olsen dis boards are really nice - my electronics bench is fitted with an example with its own double-pole MCB.
Having said that, one of its sockets feeds a couple of daisy-chained plastic multi-way extensions!
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Old 22nd Apr 2018, 8:05 pm   #28
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Default Re: Daisy Chain Mains Extensions

Quote:
Originally Posted by M0FYA Andy View Post
The choice was risk unwinding the live cable, the insulation of which was now sticky to touch, or plunge the concert into darkness.
We chose to unwind the reel and lay it out along the balcony, and got away with it.
H & S anyone?
Having spent my early life/career as a theatre electrician, I can confirm that

"The Show Must Go On" > "Health & Safety".

The average theatre fly floor is an excellent place to hunt for impromptu autotransformers constructed from nothing more than TRS. More seriously, perhaps that experience is why I'm not very concerned with "daisy chaining" since the lighting rig will be full of it, which is what the Grelcos I referred to earlier up the thread are for.

They actually are now made so that you can't stack them (the "Snapper" type), which is why every theatre will have a good stock of splitters (1 plug, two trailing sockets).

Mind you I stopped working in theatre in the 90s so I daresay it's all much more elfinsafety and so on. In my day you were being pedantic if you tried to achieve some kind of phase separation in the rig. Having said all that, the most unpleasant accident I ever experienced was grabbing a lantern that was bolted to a wooden set (hence no fortuitous earthing) whose live and earth wires had been reversed, presumably before the lighting hire company had put the "inspected and tested" sticker on it.
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Old 22nd Apr 2018, 8:38 pm   #29
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Default Re: Daisy Chain Mains Extensions

Quote:
so I could wire in my own cable
Good idea (unless it is for "sound quality") as some of the extensions I have bought are wired in a most atrocious manner, I am glad I took them apart before using. One had the earth floating around!
 
Old 22nd Apr 2018, 9:04 pm   #30
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Default Re: Daisy Chain Mains Extensions

Quote:
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Didn't a firm called Olsen in London make metal distribution strips with lots of MK sockets. Used to advertise in WW
Yes, and they will make custom assemblies

https://olsondirect.co.uk/

Or a series of metalclad sockets with conduit couplers between them, cable gland at the end(s) all mounted on a nice piece of varnished plank.
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Old 22nd Apr 2018, 9:16 pm   #31
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Default Re: Daisy Chain Mains Extensions

I have looked on the Olson site before. There are so many options, I am not really sure what I need to be looking for. Curiously i noticed most have a coiled earth wire on the side of the extension next to the mains cable.
Is that meant to be connected to anything ?
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Old 22nd Apr 2018, 9:51 pm   #32
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Default Daisy Chain Mains Extensions

Quote:
Originally Posted by IanBland View Post
In my day you were being pedantic if you tried to achieve some kind of phase separation in the rig.
As a young and inexperienced amateur lighting 'director' I once had to rig a small theatre in Edinburgh for a touring student production. I ran out of stage dips and decided to use a different phase to make up the numbers. A few hours later I was dragged back by the (professional) theatre electrician who forcefully explained the importance of phase separation and stood watching me muttering while I rerigged. He was absolutely correct of course.

Quote:
Originally Posted by gramophone1 View Post
I have looked on the Olson site before. There are so many options, I am not really sure what I need to be looking for. Curiously i noticed most have a coiled earth wire on the side of the extension next to the mains cable.
Is that meant to be connected to anything ?
Don't overthink this. You are just powering a few bits of hifi in a domestic environment. Two standard short 6 ways will be fine - don't waste your money gold plating things.
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Old 22nd Apr 2018, 10:01 pm   #33
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Default Re: Daisy Chain Mains Extensions

I must admit to daisy chaining in my den, but it's done on a load rated basis. The heaviest users -PC/lamp is on the first quad unit ,with printers/speakers /scanners on the following units. All my lead lengths are short. Biggest problem ,that is not advertised ( IMHO-well enough) is the eddy current heating effect of wind up type extension leads used for even low-moderate current consumption.
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Old 22nd Apr 2018, 10:35 pm   #34
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Default Re: Daisy Chain Mains Extensions

Quote:
Originally Posted by paulsherwin View Post
As a young and inexperienced amateur lighting 'director' I once had to rig a small theatre in Edinburgh for a touring student production. I ran out of stage dips and decided to use a different phase to make up the numbers. A few hours later I was dragged back by the (professional) theatre electrician who forcefully explained the importance of phase separation and stood watching me muttering while I rerigged. He was absolutely correct of course.
I was quite a stickler for it, but my first chief lx/mentor was an old boy from the old school who wanted everything done properly (having said that, when he retired the first thing we did was ceremonially get rid of his huge stock of aged splitters (he didn't like modern rubber plugs and they all had round bakelite plugs that I think were dated to at least the 1960s, probably older).

Such niceties as worrying about phases were falling by the wayside as the theatre industry got more and more younger people with an influence from rock'n'roll touring who didn't tend to worry about the likes of it. I was a young'un too, but as I said with a very traditional first boss who saw himself primarily as an electrical engineer.

Funny thing writing this, I can't remember the Duke Of Yorks (where I was myself chief LX) having any dip traps at all. I remember the elderly batten boxes on the fly floor that were still labelled with the batten colours (red, blue, amber, white) that fell to bits when you unplugged something (until they were replaced when I convinced management to pay for a ROH rewire) and I remember the awesome Strand Grandmaster still on its perch, but I can't remember any stage dips. I guess we must have just dropped tripes down from above, then daisychained
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Old 22nd Apr 2018, 10:51 pm   #35
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Default Re: Daisy Chain Mains Extensions

Quote:
Originally Posted by paulsherwin View Post
As a young and inexperienced amateur lighting 'director' I once had to rig a small theatre in Edinburgh for a touring student production. I ran out of stage dips and decided to use a different phase to make up the numbers. A few hours later I was dragged back by the (professional) theatre electrician who forcefully explained the importance of phase separation and stood watching me muttering while I rerigged. He was absolutely correct of course.
Just curious, what are stage dips ?
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Old 22nd Apr 2018, 10:58 pm   #36
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Default Re: Daisy Chain Mains Extensions

Quote:
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Biggest problem ,that is not advertised ( IMHO-well enough) is the eddy current heating effect of wind up type extension leads used for even low-moderate current consumption.
The heating up of coiled extension leads is nothing to do with eddy currents- there's not enough inductance to worry about that. It's simply caused by the fact that the resistive loss heat in the inner wires in the coil has no way to escape to the local environment except through many layers of poor thermal conductor (the wire insulation) so the wires heat up until the insulation melts or burns.

A quick lookup of the derating factors needed for "all cores loaded" in multiway cable will make the point...... for many cores (like in a wound up lead) derating to 25% or less of the single wire in free air rating will be needed.

Stage dips are sockets in the floor. Usually under a cover with cable entry cutouts on its edge(s).
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Old 22nd Apr 2018, 11:06 pm   #37
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Default Re: Daisy Chain Mains Extensions

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Just curious, what are stage dips ?
A proper "dip trap" is a recessed plug box in the floor (containing your sockets from the dimmer outputs) with a trapdoor on it, so you can run your cables out of it (gaffer taped to the floor) to lanterns at stage level. The trapdoor will have cutouts for the cables to egress.

In practise, any plug box at stage level (e.g. on the walls) gets called a dip, whether under a "trap" or not.

It's worth noting that wherever your outlets are, they are in the wrong place for any particular production. I think probably in the early days of electrical lighting of theatre it would be presumed you'd only be using some of the circuits, but in reality every show uses all of them. Hence the problems of phase separation Paul originally described. IIRC at the Dukes it was blue phase on the fly floor, yellow on stage and red front of house.

And having written that, we must have had dips (to be on a phase at all) but for the life of me I can't remember them at all. Not that it matters, but now it's niggling me like mad. Maybe we didn't have any until the rewire (I'm pretty sure I had wall mounted plugboxes installed).

Gaah. This is going to keep me awake tonight
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Old 22nd Apr 2018, 11:38 pm   #38
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Default Re: Daisy Chain Mains Extensions

I imagine the presence of dips mostly depends on the basic stage electrical layout, which in turn partly depends on when the theatre was built or rebuilt. They are much more common in the small rep / arts centre theatres that were built in large numbers in the 70s, originally with 30 channel Strand thyristor boards of some description. My sixth form college (opened in 1970) had this setup in its large central lecture theatre.

I have no real experience with large houses or music venues. Presumably these now have hundreds of lighting channels with computer control, and it would be pretty pointless wiring all those to recessed sockets in the stage floor.

Anyway, I'm taking the thread off topic. Back to daisy chained multiway sockets please.
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Old 23rd Apr 2018, 10:00 am   #39
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Default Re: Daisy Chain Mains Extensions

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I have looked on the Olson site before. There are so many options, I am not really sure what I need to be looking for. Curiously i noticed most have a coiled earth wire on the side of the extension next to the mains cable.
Is that meant to be connected to anything ?
The target market for Olson stuff is professional workshops/communications/data-centre - where it's most likely the outlet-strip will be fitted to a metal bench or inside a metal cabinet or comms-rack. The 'pigtail' is intended to be bolted to the bench or rack to provide earth-bonding since you can never depend on the screws/cage-nuts used to physically attach power-strip /rack together to provide a reliable low-impedance ground path (I've seen such strips attached to the insides of racks using cable-ties).
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Old 23rd Apr 2018, 4:46 pm   #40
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Default Re: Daisy Chain Mains Extensions

Some of this seems a little OTT considering the extension lead plugged into the mains socket will have a 13A fuse in the plug protecting it. Is chaining a few together going to add significant extra length when compared with the length of the socket cabling in a typical house? Also, if the earth connections in such extension boards are poor or plugs not wired properly, then they are not fit purpose, chained or otherwise.

I always thought these views came from the original multi socket blocks that plugged into a socket and had 2 or 3 sockets on them, because the originals were not fused, so very easy to overload a socket?
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