Heater connection

'Fraid what you've said doesn't make much sense.

Don't suppose you could post a drawing of the circuit?

If not, please explain more clearly.

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Six heaters in each of six zones means 36 heaters.

As John said, MUCH clarification is needed!

Try first typing your post in a word processor and use the grammar checker, then once it has been corrected, copy the text and paste it into the CR4 editor.

Sorry sir,

im prone to grammatical errors what i was trying to say is that totally in a furnace there are 18 heaters each are of 70KW rating.They are divided into three zones and in each zone there are 6 heaters respectively.In each zone the heaters are connected in such a way that h1(heater1) from zone1 ps(power supply R phase) and h2 frm ps for z2(Y phase) and heater 3 from z3ps(B phase) forming a delta loop.Similarly remaining 3 from that zone are connected in the same way forming another delta loop. Zone 1 power supply contains two outlet for R phase and 2 ouutlet for Y phase and two outlet for B phase and so will other two zones be.

The two leads of the heater will be connected to a phase of a delta loop as said and when the current is measured in two leads two different readings are shown how? there is only one coil for heating ?tell me pl...........

Ok, that is definitely an improvement! So each heater has two wires connected directly across one phase of the three phase supply, and each set of three forms a delta loop on one supply line.

Assuming (1) the supply is approximately balanced (approximately the same voltage across any two line pairs, no large single-phase loads on one phase without corresponding loads on the other phases), and (2) all six heaters are the same rating (voltage, power, current, resistance), then the current should be the same in all heaters.

If the current in one of the wires is different than the current in the other wire of a given heater, the only possible explanation is that a heater element is touching something uninsulated, most likely a short to ground. In most cases, that would burn out the heater, unless you have a floating ground. If you have a floating ground, you have a definite safety issue!

Can you follow the wires from each outlet all the way to each heater, to be sure nothing else is connected and you are measuring only the current to a single heater? Since each phase connects to two heaters, there could be a single wire leading to a 'Y' somewhere in the wiring. you must measure on the heater side of any such 'Y'.

The only other possibility I can think of is the method of measurement. To measure current, you must either use a clamp-on type meter or break the circuit to insert a current meter.

How much difference? can you give current reading? Are heaters controlled by Power Electronics to maintain temperature?

You might have a heater burn out. This would give you an unbalanced load.