Newb Question: Wiring

SageBrush

I lost the marker I had placed on one end of my circuit wire to identify which direction the wire was placed in the ground, so I need a method to figure it out. Schematically I have this:

                           |  -----------------------|  (+)
Inverter    =====                              Serial Panels
                           | ______________| (-)

One end of my serial array will be + and the other end (-)
I need to identify which wire is which to know how to connect the wires to the correct terminals in the inverter.

Thanks!

cow_rancher

Hmmm try a VOM when the sun is shining, that should be a pretty good indication.

Rancher

Lumisol

You could also use a wire tracer and tone generator.

SageBrush

Is a VOM the same as my $10 digital multi-meter from Harbor Freight ? :-)

So in this scenario:
The (+) lead from my first optimizer is connected to the (+) input of the multimeter
The (-) lead from my last optimizer is connected to the (-) input of the multimeter

The serial voltage of 12v (12 SE optimizers) would register positive ?

littleharbor2

Yes, and if connected backwards you should get a negative, - , reading.

cow_rancher

SageBrush said:

Is a VOM the same as my $10 digital multi-meter from Harbor Freight ? :-)

Yes, VOM = Volt Ohm Meter

SageBrush

Thanks very much everybody!

I feel obliged to ask one last REALLY stupid question, since I don't want to fry my inverter ...

Am I correct in saying that the black lead is connected to the (+) terminal of my multi-meter ?
I think so, since I checked positive and negative voltage values of a 3V battery of known labeled polarity, but I'd like some reassurance here ;-)

nickdearing88

SageBrush said:

Thanks very much everybody!

I feel obliged to ask one last REALLY stupid question, since I don't want to fry my inverter ...

Am I correct in saying that the black lead is connected to the (+) terminal of my multi-meter ?
I think so, since I checked positive and negative voltage values of a 3V battery of known labeled polarity, but I'd like some reassurance here ;-)

No, Red is usually positive and the Black should be connected to the COM port.

BB.

Note that you have two settings for reading voltage.

DC (solid / dotted lines) and AC (sine wave / wiggly line).

Different meters when set to AC will read DC voltages differently. Some will read DC voltage (always positive or no sign, amplitude may be correct or too high), other meters will read DC voltage as zero volts.

When set to read DC volts, reversing leads should switch between + and - readings.

- Bill

littleharbor2

Typically the black lead would connect to the common port and red to the others. It would make no difference in how your meter reads if the other way around as long as you know which is which

mvas

With DC Volts  ...
Red   is (+) Positive / Hot
Black is (-) Negative / Common 

Here is a picture of the "correct" way ...

Aguarancher

'Here is a picture of the "correct" way ...' the pic is showing the AC scale not DC..

mcgivor

Aguarancher said:

'Here is a picture of the "correct" way ...' the pic is showing the AC scale not DC..

Just what I was thinking, 750W is high voltage?  Thought  >1000 VAC  was considered high voltage, as per IEEE, but that is debatable, so no argument there.. 

mvas

Aguarancher said:

'Here is a picture of the "correct" way ...' the pic is showing the AC scale not DC..

The OP asked,
"... Am I correct in saying that the black lead is connected to the (+) terminal of my multi-meter ? ..."
The question was "HOW to connect the Red & Black Probes to the meter".
The picture shows the correct way to do that.
It is a "stock photo", turn the Dial to the correct AC/DC Range, as need.

Aguarancher

With the confusion the OP was expressing I was merely pointing out that your pic while showing correct positioning of the leads was showing AC and not DC voltage as he was requesting. This pic shows both in the correct position.