Informative Annex D Example D1(b)

[MMTCET]

Informative Annex D Example D1(b)
When calculating the 25% for largest motor for Line B why did they use 8 Amps (Disposal) instead of 10 Amps (Dishwasher)?

 

[GoldDigger]

Possibly they knew that the A/C info included a fan motor?
Or that the figure for the A/C was actually MCA, which includes the 125% already?
Or both?

 

[MMTCET]

Correction original post.

Correction original post.

The 10 Amps is for the diswasher.

 

[GoldDigger]

The 10 Amps is for the diswasher.

The full load amp rating of the dishwasher pump motor is unlikely to be 10A.
That figure probably includes the optional use of the heating element for rinsing and drying.
If the example specifically says the 10A is the motor rating, then I would expect it to be chosen.

 

[jumper]

The disposal is a full motor.

The dishwasher is a motor and a heating element. The element is a large part of the total amps of the DW unit.

Edit: Goldy types faster.

 

[jumper]

The full load amp rating of the dishwasher pump motor is unlikely to be 10A.
That figure probably includes the optional use of the heating element for rinsing and drying.
If the example specifically says the 10A is the motor rating, then I would expect it to be chosen.

AFAIK all household DWs use the element for cleaning. You only hook up a cold water supply to a unit.

 

[jim dungar]

You only hook up a cold water supply to a unit.

Then mine is hooked up wrong.:slaphead:

 

[jumper]

Then mine is hooked up wrong.:slaphead:

Durn DIYers....

You are heating hot water.

 

[jim dungar]

Durn DIYers....

You are heating hot water.

Actually I am heating warm water. I think WH is set around 120F (below scalding), DW set for 140F (above sanitizing).

 

[jumper]

Actually I am heating warm water. I think WH is set around 120F (below scalding), DW set for 140F (above sanitizing).

I was bored so I looked up a few models. The water supply line varies. Yours is actually the more common install.

Most are hooked up like yours, boosting the temp of the water out of the WH.

Others are supplied through a cold water line and use solely the DW element.

I guess the few that I have done just happened to be the latter.

 

[Dennis Alwon]

I think what they did was take the largest motor on each phase and multiplied by 125% but something does not compute for me.

 

[MMTCET]

The full load amp rating of the dishwasher pump motor is unlikely to be 10A.
That figure probably includes the optional use of the heating element for rinsing and drying.
If the example specifically says the 10A is the motor rating, then I would expect it to be chosen.

This makes sense I assumed the dishwasher was a motor load when it is actually an appliance load. Thank You

 

[jumper]

I think what they did was take the largest motor on each phase and multiplied by 125% but something does not compute for me.

Not sure I see why it does not compute for you.

Unlike a 240V load on both legs, don't say phases or this thread will never end, each leg would have to account for the largest motor load on it.

Look at 430.24, each conductor must account for the motor load and since this example uses 2 120V loads on opposite legs, it must be accounted for.