Quick question!

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Mirus Lux

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Got my new Lencarta lights today woohoo! When plugging them in is it ok to plug them both into a multi socket extension cable or should they go into separate mains plugs? Can't see any reason why not but thought I would check!
 
They'll be fine on a multi extension
 
Cheers Garry! Can't believe how quick they arrived - sent you an email!
 
Duncan.F said:
Loading is very low, most telly/stereo use more! So extension is fine
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Are you sure? I've had monos trip the thermal cutout on extension leads. I thought they sucked a lot of power while recycling.
 
If my memory serves me correct each wall plug can take 3000W's.
 
If you want to know the details, do a search for Ohm's Law but in short its quite simple. In the UK the domestic mains voltage is roughly 240v and the usual rating for a 3 pin socket on your domestic ring main is 13amps which is the maximum rated load you should plug in.

The lights and most other electrical items will have a 'wattage' shown on them and all you need to do is divide the wattage by the voltage to get the amparage.

Rule of thumb to save you getting the calculator out. If something is rated at 1kw or (1000w) it will draw roughly 4amps (1000/240). This is why most domestic heaters are a maximum of 3Kw (3000w) because 3000/240 is roughly 12 amps.

All that said, make sure your multi way extension cable is rated at 13amps and not at 5amps like some. The maximum load you can plug into a 5amp multiway is about 1200w.
 
iPhoto said:
If you want to know the details, do a search for Ohm's Law but in short its quite simple. In the UK the domestic mains voltage is roughly 240v and the usual rating for a 3 pin socket on your domestic ring main is 13amps which is the maximum rated load you should plug in.

The lights and most other electrical items will have a 'wattage' shown on them and all you need to do is divide the wattage by the voltage to get the amparage.

Rule of thumb to save you getting the calculator out. If something is rated at 1kw or (1000w) it will draw roughly 4amps (1000/240). This is why most domestic heaters are a maximum of 3Kw (3000w) because 3000/240 is roughly 12 amps.

All that said, make sure your multi way extension cable is rated at 13amps and not at 5amps like some. The maximum load you can plug into a 5amp multiway is about 1200w.
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As above. If you look at the all-important information plate on the bottom of your ElitePro 300 you'll see that the wattage is 350 - that's basically 300 watts for the flash energy and 50 watts for everything else. Add 250 watts for the modelling lamp and you end up with 700 watts. divide that by the voltage and you end up with just 2.917 amps per head.
 
The length of the extension lead is also a factor to be taken into account, as well as the CSA of the cable.
 
Garry Edwards said:
As above. If you look at the all-important information plate on the bottom of your ElitePro 300 you'll see that the wattage is 350 - that's basically 300 watts for the flash energy and 50 watts for everything else. Add 250 watts for the modelling lamp and you end up with 700 watts. divide that by the voltage and you end up with just 2.917 amps per head.
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You sure that's right? I think legally, the information on the plate needs to be the maximum rated so should include the modelling light and any recharge current.

Also, it depends on how long it takes to recharge as to the current actually used.
 
Garry Edwards said:
As above. If you look at the all-important information plate on the bottom of your ElitePro 300 you'll see that the wattage is 350 - that's basically 300 watts for the flash energy and 50 watts for everything else. Add 250 watts for the modelling lamp and you end up with 700 watts. divide that by the voltage and you end up with just 2.917 amps per head.
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So 2 X 600 and a couple of 300s = about 18 amps? I wondered why the cable was hot to the touch.
 
Tugster said:
The length of the extension lead is also a factor to be taken into account
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Please explain?

JonathanRyan said:
So 2 X 600 and a couple of 300s = about 18 amps? I wondered why the cable was hot to the touch.
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Cables dont mind slight short term increases to the current above rated value, and I can only imagine that even with this load the lights would have to be all set at maximum and fire quite frequently to draw a load that would cause concern to the cable/multi-way/fuse.

However, being cautious, if you know you are to draw more than the rated current of the cable/multi-way/fuse on a continuous or frequent basis, shouldnt you consider spreading it out around a bit?

On a side note, at low level overcurrents you cannot always rely on the fuse to blow before damage occurs.
 
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The resistance of the cable will increase with length...The higher the resistance the more loss/heat will be generated...This is why the longer extension leads that are available commercially are of a thicker/greater CSA cable than the shorter ones.

I hope that wasn't too technical
 
Also if you have the extension on a reel it will need to be fully unwound. Doesn't take much load to heat it up. Most 13amp leads of average length are 1.5mm cable which will take about 18 amps. The only time I've seen a lead melt is either it's been left in a coil or it's had a loose connection.
 
Tugster said:
The resistance of the cable will increase with length...The higher the resistance the more loss/heat will be generated...This is why the longer extension leads that are available commercially are of a thicker/greater CSA cable than the shorter ones.

I hope that wasn't too technical
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Too technical and possibly a tad too sarcastic for a Friday night.

My competency is 3 phase high power LV and secondary distribution HV so I might be off here. Connect a load drawing 13 amps down a 1 metre long 2.5mm sq cable and it has an impedance of X which causes a heating effect and a voltage drop. Same load same cable but 100 metres long and you get the same heating effect per metre but you get a cumulative volt drop which may cause problems at point of load. Way to overcome volt drop is to increase csa, hence longer cables tend to be oversized.

Apologies if not relevant to domestic systems and too technical ;-)
 
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i think a set of 400A 3line powerlock leads fed from a 250KVA diesel genny should cope :P
 
Haha, I'll have to dig out a pic of the feed I was using to throw 12 lights around a tv set the other week...

Strobes surge in power draw when they recycle, but when not recycling they have a relatively low current draw above the power of a modelling lamp. If you shoot loads and fast, It's going to put a relatively high load through the cable and you should definitely fully unwind the whole long extension lead, to stop it from turning into a kettle and melting.

Eg a super fast profoto 8a pack can recycle 2400ws of energy in under a couple of seconds - you want to be giving that its own mains socket :)

The profoto 7B has two 30A fuses on its battery, lol...

One or two monoblocs will be fine, but I'd hesitate and try to avoid running more than 3x 600s off the same plug socket, maybe even two if I knew I was going to be shooting at full power and with modeling lights - if only to leave some margin in case a MUA plugs in a hairdryer or something :lol:

But OP: yes, it'll be fine.
 
Mmmm getting a bit technical! It is good practice and a good idea to unwind and extension as heating does occur when cable has a loading and is coiled up.
However all currents produce some heat and cables should be rated for a particular temperature range. Household flexes and the grey cable used for house wiring are rated at 70 deg C, heat resistant is rated at 90. However, the plug tops and extension sockets are generally not!
Extension leads are sold in 4 main sizes, 0.75mm/1.0mm/1.5mm/2.5mm. These should have different ratings and fuses as the load they can take will be quite different. So when you buy you should ensure that you get one that is rated at 13amps, this is the total loading of the lead so if you have an extension with 4 sockets on the total lead shouldn't exceed that.
Yes roughly 4 amps to a 1000w or 1 KW. Studio lights have some fairly complex electronics, some with multiple capacitors and recharge typically in a very short space of time, maybe 1/2second to 4seconds. There will be a high load therefore for a very short period of time, so if you are banging off one shot after another the cable will get warm/hot depending on the load.
I have run 4 x 750 off one extension without too much trouble but I wasn't using them continuously.
But to return to the OP, running a few lights off one extension lead of the right rating is no problem! If you were running say 4 or 5 lights maybe think about using two extensions.
Hope this is helpful!
 
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