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Chaining multiple stingers


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#1 Will Edwick

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Posted 08 February 2016 - 01:25 PM

I'm just wondering how safe it is to run a 2K light (with circuit breaker) off a 13 amp home circuit (UK) through a chain of 3 or 4 single 20m stingers? I know people usually recommend avoiding daisy chaining but we'd only be running that one light off that single chain.

 

Cheers!


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#2 Jay Young

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Posted 08 February 2016 - 01:57 PM

Can you not just spend $ and buy a 50' cable?  Seems more safe.


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#3 Mark Dunn

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Posted 08 February 2016 - 02:18 PM

 

 

a 50' cable? 

 

20m is 65'. So OP is talking about at least 200'. 

 

There's a calculator here

https://www.tlc-dire... Min Cable Size

which suggests you're OK up to about 50m with standard extensions, which are 1.5mm squared. A 2K only draws about 8A so you're OK in theory There's a bit of voltage drop as you see.

If you can find a heavy-duty cable it would be better.

Keep an eye on the cable and make sure it is fully unwound otherwise it will act as a heating element and get a bit hot.

Just make sure they're not light-duty 6A extensions.


Edited by Mark Dunn, 08 February 2016 - 02:31 PM.

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#4 Jay Young

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Posted 08 February 2016 - 03:03 PM

Woops!  I missed that 20 METER part...


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#5 Will Edwick

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Posted 08 February 2016 - 06:13 PM

Thanks for the replies guys! The cables we've got are definitely 13 amp but not sure how thick they are. Would getting a 13 amp to 16 amp adapter and getting longer cables make things easier/safer?

 

Cheers


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#6 Mark Dunn

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Posted 09 February 2016 - 02:30 PM

If the extensions say 13A they will probably be 1.5mm squared. You should be OK safety-wise but the voltage drop will be a bit more.

By adapter do you mean one of these?

http://uk.farnell.co...ross_price=true

These 16A extensions would use one to plug into a domestic circuit, but of course the circuit is still only 13A.

http://www.mad4tools...q-lrxoCFL_w_wcB

 

For a one-off shoot I'd probably go with what I had, personally, unless there's a budget for things you can use later.


Edited by Mark Dunn, 09 February 2016 - 02:42 PM.

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#7 Will Edwick

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Posted 09 February 2016 - 03:37 PM

The adapters have a 13A socket with a bit of cable running to a 16A socket on the other end so slightly different to the one you linked. Would the voltage drop still be the same if we used an adapter? And would it be any more safe?

 

Cheers


Edited by Will Edwick, 09 February 2016 - 03:38 PM.

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#8 Stuart Brereton

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Posted 09 February 2016 - 07:13 PM

The voltage drop has to do with the length of cable you're using. A 16 amp adapter is not going to change that.


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#9 JD Hartman

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Posted 10 February 2016 - 09:32 AM

....and the voltage, amperage draw and the gage of the conductors.  There are calculators available on the web that do the math.


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#10 Mark Dunn

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Posted 10 February 2016 - 09:51 AM

OP, you'd only be looking at a colour temperature drop of a couple of hundred kelvins at most. Quite tolerable IMO.


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#11 Phil Rhodes

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Posted 10 February 2016 - 10:39 AM

I've run stuff from a 16A cable 100m long in the past. The (basic, iron-ballasted) HMIs did get a bit brighter when we unplugged the wallpaper steamer that was being used as a physical effect.

 

P


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#12 aapo lettinen

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Posted 10 February 2016 - 11:05 AM

with student films we did this all the time, the 1.5mm cable should do if you don't have anything else but it is much better if you can get some 2.5mm or 4mm cable to start the chain so that the voltage drop is lower and they don't heat as much. 

HMI lights may have serious issues with a 100m 1.5mm chain so it is best to avoid it the best you can.  if it can't be avoided, you can use two or more chains on separate fuses and lower wattage (maybe 30-40% of the rated amp) per chain so that you don't run into problems.

I think we did something like 150m for about 1.5kw once with 2.5 and 1.5 cords though not very practical compared to a genny and we fried a stinger or two when added 100w more to the chain  <_<  


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#13 aapo lettinen

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Posted 10 February 2016 - 11:16 AM

with tungsten lights it is not much of an issue if the colour temperature changes little, your main concern is whether the stingers and sockets get too hot and melt or even burn if your chain is too long /too many watts for the cord. something like 60°C is quite normal for heavy use but if they are burning hot then you should definitely switch it off and change the light to a 1k  :ph34r:


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#14 Mark Dunn

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Posted 10 February 2016 - 12:09 PM

,  use two or more chains on separate fuses and lower wattage (maybe 30-40% of the rated amp) per chain so that you don't run into problems.

 

OP wants to run a single head- is there a way to run two leads in parallel on single-phase without re-wiring?


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#15 aapo lettinen

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Posted 10 February 2016 - 12:34 PM

OP wants to run a single head- is there a way to run two leads in parallel on single-phase without re-wiring?

no, you have to either re-wire it or use more sturdy cable for a part of the chain to fight the voltage drop. if you had 16amp 3-phase cable you could re-wire it to single phase and make at least 200 -250m run with it but it is tricky and also may be illegal in GB, I don't know :/  

 

I would just use 2.5mm cable as much as possible and if absolutely necessary I could add some 1.5mm


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#16 aapo lettinen

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Posted 10 February 2016 - 01:12 PM

in the case of very long runs for student films we usually had some kind of 3 phase outlet we could use, either 16 or 32a. I think the longest run was over 250m from single 16a 3-phase outlet to two 1.8k arrisuns, a kobolt 400 and couple of arri 200 fresnels. 

I started with a 16A to 32A adapter, used all the 32A cable I could find (about 100m of it), added distribution box to convert to 16A cable, used all the 16A 3-phase cable, maybe 120m of it, and then continued with 2.5mm extension cords. it worked fine for the arrisuns but it was one phase per AS18 and the third for the rest of the stuff. I think the AS18 takes something like 2200-2300w when in full power, I metered it once but can't remember anymore...


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