Commercial dishwasher

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  #1  
Old 03-11-13, 03:21 PM
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Commercial dishwasher

I am replacing a dishwasher. The current dishwasher is wired up with 3 black wires and one white wire. The new dishwasher has 1 black,1 red,1 white and 1 green. How can I hook these up?
 
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  #2  
Old 03-11-13, 03:43 PM
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Welcome to the forums!

We'll need some more information. What is the wiring for this circuit at the panel? What is the nameplate information for each dishwasher?
 
  #3  
Old 03-11-13, 04:45 PM
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Thanks..

Its ran to a dual 50amp fuse..
NEW
is 120/208-240 VAC
4 Wire single phase

OLD
is 120/208-240
(3W)
 
  #4  
Old 03-11-13, 04:52 PM
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Thanks for the quick reply.

Its ran to a dual 50amp fuse..
A dual fuse, or 2-pole circuit breaker? Where is the third wire black wire connected at each end?

What is the amp draw of the new dishwasher and what size are the wires? Does the new dishwasher list the maximum overcurrent protection?

It sounds like the wires are in conduit. Is that the case? Is it metal conduit?
 
  #5  
Old 03-11-13, 05:23 PM
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Three black wires sounds like three phase not single phase. Are you sure is doesn't at least have three phase heaters? As Nash asked:
Where is the third wire black wire connected at each end?
4 Wire single phase
Would be two hots, a neutral, and a ground. That isn't what you say you have.
 

Last edited by ray2047; 03-11-13 at 05:42 PM.
  #6  
Old 03-11-13, 06:16 PM
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ok here are some pics of what I am dealing with.. The one black wire has white tape on it ant then it connects to the grounding block in the box along with the white wire. The other two black go into the breaker as shown..
 
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Old 03-11-13, 07:19 PM
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The current dishwasher is wired up with 3 black wires and one white wire.
OLD
is 120/208-240
(3W)
If the current machine is the old machine, the current machine was a 4-wire hookup, not a 3-wire. A black wire (marked with white phasing tape) was obviously used as a ground although it should have been a green conductor. If the picture is of the label on the current machine, it is also a single phase 4-wire hookup. You didn't mention it, but you also need a means of disconnect at the machine.
 
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Old 03-11-13, 07:38 PM
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But since the wire is smaller then #4 a black by code can't be remarked. You should, as Joe pointed out, pull a correctly colored ground wire to be code compliant.
 
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Old 03-11-13, 08:17 PM
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"If the current machine is the old machine, the current machine was a 4-wire hookup, not a 3-wire. A black wire (marked with white phasing tape) was obviously used as a ground although it should have been a green conductor. If the picture is of the label on the current machine, it is also a single phase 4-wire hookup. You didn't mention it, but you also need a means of disconnect at the machine."

Not sure how to quote... The 3 black wires are coming from the fuse box and they were hooked directly up to the old washer.. The name plate on the washer says 120/208-240(3W) i just posted information I can read on the plate. so is this the way it should be hooked up?

new red --- one black

new black --- other black

new green --- black with white tape (pull through a new green wire for code)

new white --- old white
 
  #10  
Old 03-11-13, 08:19 PM
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One of your pictures shows 4 wires - a black, red, white and green - in a piece of Greenfield. Is that the end that goes into the dishwasher? If so the wires may be correct (depending on the size needed) but the piece of Greenfield should be replaced with Liquid Tight conduit. Another picture shows four different wires - two blacks, a black with white tape and a white - in a connector. Assuming that is the end at the panel and the two black wires were connected to the breaker, the black marked with white tape needs to be replaced with a green wire.

If the wiring is run in metal conduit, that may serve as the path to ground. You will need to test it to be sure.

What is the full model number of the new dishwasher? Is it a used machine?

What amperage does the dishwasher require? And what size are the wires you have now?
 
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Old 03-11-13, 08:42 PM
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ok the pic with the black wires in the connector i disconnected from the old dishwasher. so it goes in the wall then to the box. the other pic of the 4 colored wires is connected to the new dishwasher with the condut around it like shown.. The new dishwasher is actually not new it is used.
 
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Old 03-11-13, 09:19 PM
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ok the pic with the black wires in the connector i disconnected from the old dishwasher. so it goes in the wall then to the box.
Then the wires are not code compliant in regards to color. There should be one green ground, one white, and either two blacks or a black and red. By code you an not use a #6 or smaller black as ground even if you redesignate it with tape. The wiring from the breaker (not fuse as you wrote) must be changed to comply with code.

What gauge wire is that it should be marked on it somewhere. You may need to increase the breaker to 55 or 60 amps so you need to be sure it is #6. What size breaker does your instructions call for?
 
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Old 03-11-13, 09:39 PM
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the other pic of the 4 colored wires is connected to the new dishwasher with the condut around it like shown..
Originally Posted by Nashkat1
the wires may be correct (depending on the size needed) but the piece of Greenfield should be replaced with Liquid Tight conduit.
The new dishwasher is actually not new it is used.
Do you have the instructions for your good used dishwasher? What is the full model number?
 
  #14  
Old 03-12-13, 09:25 AM
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Ok the model no is UH-150B-70.
 
  #15  
Old 03-12-13, 10:38 AM
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Ok the model no is UH-150B-70.
Now we're getting somewhere!

Your photo shows that your dishwasher is rated at 55 amps on a 240V supply. The Spec Sheet for the Champion UH-150B shows that a UH-150B dishwasher rated at 55 amps on 240V has a 70F/39C Rise Booster. That may be what the 70 at the end of the model number stands for. Regardless, the Minimum Supply Circuit Conductor Ampacity for your new dishwasher is 70 amps and the Maximum Overcurrent Protective Device must be rated at 70 amps.The machine must also be hardwired.

That means that the existing 50A 240V circuit breaker must be replaced with a 70A 240V circuit breaker made for that panel. From the panel to the dishwasher you will need three #4 AWG copper conductors - black, red and white - and one #10 AWG green copper conductor. Since this is an undercounter model, you may not have to install a disconnect near it, but you may. Check with your inspector about that. You may also need to use liquidtight conduit in the area where the machine is located. Again, check with your inspector.

In the panel, the red and black wires will connect to the circuit breaker. If you only have a common bus with both neutrals and ground connected to it, then both the white and the green wire will go to that.

At the dishwasher, the black and red wires go to the terminals marked L1 and L2 - it doesn't matter which goes to which. The white wire goes to a terminal marked N. There should be a lug on the frame of the machine for connecting the green ground wire.
 
  #16  
Old 03-12-13, 01:48 PM
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Thanks I am going to start this today and see if I can get it done tonight..
 
  #17  
Old 03-12-13, 06:19 PM
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Not sure how to quote... The 3 black wires are coming from the fuse box and they were hooked directly up to the old washer.. The name plate on the washer says 120/208-240(3W)


But the picture of the data plate that you posted clearly says 4 wire.
 
  #18  
Old 03-12-13, 07:04 PM
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But the picture of the data plate that you posted clearly says 4 wire.
So does the Spec Sheet .
 
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