How to properly monitor a 20/50 quadplex breaker?

[sbisordi]

I have a 20/50 quadplex breaker—the outside 20s have a common trip, and the inside 50s have a common trip (picture attached).  Is this effectively a single 240v 20a and 50a breaker?  Will I need to clamp a sensor on all 4 wires to accurately monitor it?

On a side note.. what’s the point of a quadplex like this?  Is it simply to save space (using 2 spaces instead of 4)?

[djwakelee]

I had to do some research – never seen such a thing before.  So each of those 4 individual breakers are half  height – with a common trip bar on the inside, and a separate trip for the outer ones.  In the space that occupies, you could normally only put 2 120V (single) or 1 240V (dual) breakers in that spot.  But at half height, you can fit twice as many breakers.  You may have seen dual breakers that fit in a single slot.  In that case, both circuits are on the same phase.  This special animal allows you to have two 240V breakers in one 240V spot.  Because the adjacent 1/2 height breakers are on the same phase, you have that weird trip arrangement so you can get the two phases joined.  And you can get these in mixed currents, like your dual 20 / 50 A.  But basically this breaker just lets you put (2) 240V breakers in the spot that could normally have just (1) 240V breaker.  Neat.

You will need either 2 clamps or 4 clamps to monitor the two 240V circuits, depending if the loads are balanced or not.  If the 240V circuits go to an AC compressor, pump, hot water heater, or EV charger – they are balanced and you just need 2 clamps (1 for the 20A circuit, 1 for the 50A circuit).  Then you need to use the 2x multiplier in the app.  If however these breakers go to a sub panel, dryer, range, or hot tub – those are typically unbalanced and you need a clamp for each phase (4 total).  Easy to tell – just see if a neutral wire goes with that circuit out of the panel.  If the circuit uses neutral (in addition to ground), the load is unbalanced and you need 4 clamps.

 

• This reply was modified 1 year, 8 months ago by djwakelee.

[Peter]

This is 3 circuits to the Vue. two separate 120 volt, with one CT each. one 240 volt circuit with one CT and a 2.0 multiplier.

[djwakelee]

That is not correct.  The quadplex breaker provides (2) 240V circuits – in the same size breaker spot normally that would just fit one.  From the Vue standpoint, you’d need 2 to 4 clamps, depending on if the 240V loads are balanced or not.

[Author]

Posts