i have been using 2 600w hps running on a timer which is able to run up to 3000w or 4 600w hps lights. i was sent a device that reads the amount of electric you use on a real time basis it gives cost, kwh an lots of other handy readings from my leccy company, when i have it running 2 x 600w along with everything else that i use daily like tv an such it says im using around 1.8kw it does fluctuate by 100-200w sometimes but not usually, it generally stays at 1.8 asmy standard usage runnin 2 lights
so my problem is this i noticed that when i plug my 3rd hps into the same timer my electric only goes up to 1.9-2.1 kw so my extra 600w is using less than half the 600 watts is supposed to somehow
ive obviously taken into account other devices that are either on or off but even when nothing else changes but the extra 600w goin on or off the elec only goes up or down by an avg of 200w. ive also been checking this for weeks now so its not a new thing.
any clues as to wots goin on, i notice no difference in lamp brightness so cant see it effects the lamp on a physical level i jus wanna check its actually safe.
ohe yea its a powerplant ballast brand new pretty much.

It'll be some kind of error, or error margin at least, with the measuring device.

¿Have you tried metering just the 'extra' 600W ballast/lamp on their own to see what amount they appear to draw solo?

You say that you have a timer that's rated for 3000W - ¿are you sure that's not just the resistive rating (HID lamps present a capacitive, inductive load)?

I ask because 3000W is a common resistive load rating for a lot of domestic timers - this won't affect the power draw measurement, though.

If it is just the resistive rating, you *need* to be using a contactor with those HID lamps along with the timer.

Sounds like it could be wrong.

If you want make sure you can get a power meter that you can plug the light into and get the real reading off it.

If you can't see a difference in the light then it sounds like it's reading it wrong.

im sure the timer says its for up to 3000w thats wot i was told when i bought it from a hydro store about 7 years ago anyway. doesnt have a contactor its jus got it all built into it, called an ecoswitch, its defo made for growing though. has a big timer switch box then it runs to a 4 plug adapter all off of one main socket which is handy. havnt seen one on sale for a very long time tho.
i dont think the meter is not reading right as it works when i put other appliances on or off it picks up the diff from 100w or my tv or wotever else. but il try it with jus that one hps on an see if it reads correctly a bit later on. probably is jus mis readin it somehow

Oh, if it's an Ecoswitch then it'll be OK.

It sounds like the power meter might be more accurate measuring resistive loads than capacitive and inductive ones, maybe.

doesn't matter, the 600w is resistive, watts is the resistive power, the reactive power, (VAR) wouldn't show up in the watts reading (but would show up in the VA or VAR reading if it has one) so a watt meter should pick up the watts no matter the capacitance/inductance of a circuit, ALL circuits (even just two cables running side by side) have both capacitance and inductance


all of this aside though. your 600w lamp will definitely be using more than 200w, for example my sunmaster compact uses 679-690watts total. the meter is reading wrong for whatever reason, could well be the harmonics caused by the lamp, although harmonics generally make power meters read higher, never heard of them making one read lower. something is definitely amiss with it though. as said, try it with JUST the ballast/lamp running. get a picture of the display up if you can

ok i tried it with the jus the single ballast an it read it was using over 600 which is correct, but when i have all 3 on it reads less an it should use a lot more,
il check it later on a put up some pics thanks for the replies anyhow.