Control gear cable length

gigman333

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hi all
maybe someone can help?
what is the maximum length of cable i can use from my control gear to my mh fitting
i bought 3x 150watt fittings
any heip would be appreciated
 

viper357

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It is generally recommended to be less than 1m, the shorter the better, I think it also makes a difference if you are using magnetic or electronic ballasts.
 

DragonReef

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16 amp is fine.
Check on the ballast, it should give you maximum cable legnths
 

gigman333

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hey makaeel
it is a magnetic balast i was hoping to go about 1.4 metres long
 

neilharris

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On a magnetic ballast, you may be lucky to get away with 1.4m. It will do no harm to try as if it is too long, the lamp will not fire easily and may just flash slightly. NOT very good for lamp.
Personally, I would try get them closer, even if mounting above the reflectors.
The other option is to get electronic bllasts, depending on manufacturer, they can be mounted up to 4m away.
HTH,
Neil:thumbup:
 

Reef Maniac

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... what is the maximum length of cable i can use from my control gear to my mh fitting. i bought 3x 150watt fittings...
This would depend on the TYPE of (electro-magnetic )ballast - quoting from the Philips OEM Lamps and Control Gear catalogue:
  • Type BSN 150 L307 TS ballast with serial ignitor: Max. current draw = 1.0A, max. cable length = 1.0m (interestingly, the 250W and 400W ballasts allow a maximum cable length of 1.5m)
  • Type BSN 150 L34 TS ballast with semi-parallel ignitor: Max. current draw = 1.2A, max. cable length = 10.0m
The reason why the cable length plays an important role is not due to the current flowing through the cable, but rather because of the voltage created by the ignitor during start-up - some 4000 volts !

We normally use serial ignitor ballasts for our tank lights, as they are slightly cheaper, a lot easier to find in your "normal" electrical supplier's shop, and easier to wire up. In this configuration, the ballast and ignitor are mounted close together, and as close to the lamp as possible.

The semi-parallel ignitor ballast is designed for street lamp use, where the ballast sits in the bottom of the lamp pole, and the ignitor is mounted in the luminaire, close to the lamp - hence the cable length can be substantially longer.

Hennie
 

gigman333

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thanks hennie
mine says external superimposed ignitor
150w/1.80A/0.43/tw130/t70
 

DragonReef

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Nice info, thanks Hennie.
 

Hill

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My control gear clearly states up to 10m and it is magnetic. So it boils down to each manufacturer has their own parameters. Does it not state on the control gear?
 

gigman333

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no it dosnt i will phone radiant today and speak to there teck guys
see if they can get the specks
 

jacquesb

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Cool! Thanks Hennie/Gigman! Even though I have 2 x of these same metal halides (my cable is +-1.2 metres long) I never bothered to worry about it.... so now I know too. 2.5 metres... cool!
 

Reef Maniac

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My control gear clearly states up to 10m and it is magnetic.
Then it is most likely a semi-parallel circuit - and nothing wrong with that :)

my cable is +-1.2 metres long
Like most things in life, there are tolerances on the ballast, cable, etc, and the manufacturers specify their products to work properly at minimum spec, so one can stretch the envelope somewhat... I too ran 150W MH's with ~1.4m cables (but I did use rather thick wires.

Hennie
 

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