[Connecting an Electric Boiler] 240v breaker(s)

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Old 01-30-16, 03:47 PM
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[Connecting an Electric Boiler] 240v breaker(s)

I installed a new boiler a NextGen- 14.4kw. 240v. The manualhttp://nextgenboiler.coopwebbuilder2...SA%20rev20.pdf Says to "use 10awg or larger wires", I used 8 NM, only about 4' from the panel to the boiler, ends up being about 10' of cable as I had to go through this off peak CT thing. The manual also says to use "[email protected] 40 amp" breakers. So I got a Siemens double breaker the says "40" on each of the two levers, the levers are joined as well as the bodies of the breakers. But it (they) keep tripping, after five minutes or so. They are also warm, not hot. Did I use the right breaker?
I question myself not only because it keeps tripping, but the manual says for the smaller boilers, still 240v, to use "[email protected] 40 amp" breaker. How would you do that with two wires and 240v?
 

Last edited by ray2047; 01-31-16 at 04:03 PM. Reason: Modify title.
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Old 01-30-16, 04:12 PM
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If it says use 2 each 40 amp breakers, and you use only one, something ain't gonna work right. Can you post a picture of the electrical hook up block in the boiler? Using 2 each 40 amp breakers you will be using 4 wires to power the boiler.
 
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Old 01-30-16, 04:18 PM
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The manual also says to use "[email protected] 40 amp" breakers
Electric heat that uses 60 amps or more usually has two 240 volt feeds off of two 240 volt double pole breakers.
"[email protected] 40 amp" breakers
If you are quoting that correctly that means you need two 240 volt double pole breakers. Just checked the PDF. I am correct you need two feeds on two separate 40 amp double pole breakers. Please wait for a pro to tell you how to connect them. Do it wrong and you have a dead short.

Did you also run a separate 120 volt circuit for the circulating pump? From the manual:
5.
The circulating pump requires a separate 120 VAC, 15 amp electrical service..
 

Last edited by ray2047; 01-30-16 at 04:46 PM.
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Old 01-30-16, 04:57 PM
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So I would put two 8 gauge wires under each lug? Attached is a picture of the lugs. Would I have hurt anything? I ran the right voltage, but it was drawing two much amps through too small of wires and breaker?

I did hook up 120v for the pump.
 
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Old 01-30-16, 05:13 PM
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Please wait for the pros. I have never wired something like this. I think I know how and know for sure how not to wire it but I'm not sure enough to give you instructions.
 
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Old 01-30-16, 05:41 PM
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You've got a problem. If that unit is indeed the 14Kw model then it is not wired correctly. A 14kw heater draws over 60A and would not be connected to one breaker.

You may have to connect two #8 cables directly to the contactors. That IS NOT covered in the manual. That manual is not complete in that it does not cover the proper installation if your unit.
 
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Old 01-30-16, 05:53 PM
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So I would put two 8 gauge wires under each lug? Would I have hurt anything by just running the two wires? I ran the right voltage, but it was drawing two much amps through too small of wires and breaker, right?
 
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Old 01-30-16, 05:55 PM
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There are two separate heating units controlled by two contactors. At this point..... in your heater they are combined..... that is not correct.

You would need a different splice block or the TWO circuits get connected directly to the contactors. However..... this wiring is not shown in that manual and should not be attempted without company confirmation.

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I wouldn't do anything until I talked to the company. You NEED 2) 40A circuits to run that heater.
 
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Old 01-30-16, 06:09 PM
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Thank you all for the help. I will ask the manufacturer. But if I were to connect two wires under each lug they would have to be from the same leg in the panel, right?
 
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Old 01-30-16, 06:18 PM
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That connection block shown in the picture you posted is NOT designed for two wires under one set screw. That's the problem. You need two completely independent circuits. Plus.... you cannot combine the output of two breakers.
 
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Old 01-30-16, 06:21 PM
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But if I were to connect two wires under each lug they would have to be from the same leg in the panel, right?
Yes or they go BOOM. .
 

Last edited by ray2047; 01-31-16 at 05:03 PM.
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Old 01-30-16, 06:33 PM
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I just had a thought.... are you sure you have the NextGen- 14.4kw model ?
Is there a tag confirming that model on your unit ?
 
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Old 01-30-16, 06:40 PM
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Specification and actual wiring inside boiler doesn't seem to match.
Specification asks for [email protected], but there is only one terminal block and both heater elements are connected to that terminal block.

From what I see you have 2 options.
Run 6 AWG wires to that single terminal and install 60A double pole breaker.
or
Run another set of 8 AWG wires on 40A breaker. Remove wires from terminal of relay (contactors) marked K1 and K2 on electrical diagram. Connect each set of 8 AWG to terminal of K1 and K2.

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K1 is feeding H3 and 24V transformer. K2 is feeding H2 and H1.
Control circuit and pumps are on separate 120V line.

BUT! Please DO confirm with the manufacture. Something just doesn't seem right.
 
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Old 01-30-16, 06:54 PM
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There is a tag confirming the 14.4kw and the 49,xxx btu. Also if it wasn't at least the 12kw it wouldn't trip the breakers. Or were you thinking something else?
 
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Old 01-30-16, 07:11 PM
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60amp is the rated current, so would a 60amp breaker be too small? And yes I will do nothing before talking to the manufacturer. But I appreciate trying to work this out ahead of time.
 
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Old 01-30-16, 07:21 PM
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This is a bigger picture.
 
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Old 01-30-16, 07:34 PM
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A 60A load on a 60A breaker will trip the breaker.
 
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Old 01-30-16, 08:34 PM
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60amp is the rated current, so would a 60amp breaker be too small?
Yes. I failed to notice it is actually pulling 60A not just asking for 60A breaker.

You would need 70A breaker and 6 or 4 AWG depending type of wire.
 
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Old 01-31-16, 07:43 AM
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I heard back from the manufacturer rep. On a Sunday! He said;

UL has approved the wiring method with this connection block to place 2 wires under the same connection. Just make sure the wires are the same phase. The other option is to place a larger breaker with a single wire for each L1, L2 and ground connections.

So what do ya'll recommend?
 
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Old 01-31-16, 10:05 AM
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Aside from boxing this thing up and returning it, the instructions you received really don't make sense. Why use two breakers when one will suffice, and why have wiring doubled up on a screw connection when only one is needed?? Don't modify any of the wiring inside the box. Use a 70 amp breaker and #4 wiring to the L1 and L2 lugs, if it will fit. I have my doubts.
 
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Old 01-31-16, 10:19 AM
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I'm checking further but I'm fairly certain by code..... the largest single breaker that can serve a piece of heating equipment like this is 60A. Hence the need for two breakers.

You cannot reconnect/combine the lines from two breakers on one set of terminals.

There is a fine line with heating units/electric boilers in that they could be considered a continuous load. I would consider that boiler a continuous duty appliance (on for more than three hours) requiring the supply circuit to be derated by 80%.
 
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Old 01-31-16, 02:28 PM
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still don't know what to do.

Since I am a novice, at best, what do I do? Does it make sense what the rep said " UL has approved the wiring method with this connection block to place 2 wires under the same connection"? I need to use this boiler, I could likely downsize but I don't know if they would take this back.
The (two) knockouts are 3/4" I don't know what I could about conduit. I would have to run conduit to use no NM, individual wires.
 
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Old 01-31-16, 03:54 PM
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Does it make sense what the rep said " UL has approved the wiring method with this connection block to place 2 wires under the same connection"?
You need to call back and escalate it to at least tier 2 support.

Or call a heating company that installs this type of boiler to hook it up.

Because of the direction this post has gone I am moving it to Boilers. Maybe someone there can answer your questions.
 

Last edited by ray2047; 01-31-16 at 05:00 PM.
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Old 01-31-16, 06:56 PM
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Boiler wiring help. Manufacturer says to do it wrong?

To get enough amps should I put two wire under each lug? Combining power from two breakers?
 
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Old 01-31-16, 08:00 PM
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If you do try it just be sure to use a multimeter to determine which two wires go to a pair. The pair to a terminal should read ~0 volts between the wires of the pair going to the terminal. (I know you already asked and was answered but it bears repeating.)
 

Last edited by ray2047; 01-31-16 at 08:18 PM.
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Old 02-01-16, 06:56 AM
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possible solution

I checked, a #4 will fit the lugs of the boiler. So unless someone has an idea I will wire it with two THHN #4 to a 70 amp breaker, and a #6 for a ground. But I will have to put that in conduit, I don't know that the will fit, there is 3/4" knockouts on the boiler.
 
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Old 02-01-16, 07:11 AM
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Ground can be #10 copper. " EMT will hold two #4 and would serve as ground so no ground wire required but probably a #10 ground will fit in " conduit with out a real problem since it is only a four foot pull or code allows ground to be run separate. You could use a step drill to enlarge the knock out to one inch then you could use up to four #4 so you would have plenty of room for ground but I don't think that is needed.
 
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