Wiring in my pump controller for new heating system yesterday and I blew the fuse

gttra88

Looking for thoughts on where I went wrong. Wiring blew the fuse (maybe transformer too) in pump controller (azel SP-84) for new heating system. Looks like it also may have fried the digi stats I had connected to the controller for 24v power

I’m installing a hydronic heating system with a Noritz NG combo-boiler. I have a 30-amp circuit running to my utility room for my current water heater. The new combo-boiler will take care of heating and domestic hot water so I decided I’ll tap into that line to run my boiler electric and all zone pumps for my system. 

  

I have a junction box in my utility room with a circuit coming down to amother box where I have a GFCI that I plan to plug the boiler into. The GFCI feeds another outlet in the same box and then that outlet hardwires into the pump controller. See pics below for wiring of outlets and pump controller. I believe I followed the directions of the controller, but when I turned on the power nothing happened. I hit the reset button on the GFCI I heard a pop from the pump controller and smelled an electrical burn. The load side neutral screw on the GFCI is also burnt and the circuit tripped. 

Any idea what I did wrong? Looking at my pictures I see that the wire on the neutral line into the GFCI looks loose on the screw. I’m not sure if I had already started to unscrew it before I took this pic or not. I know a loose connection on the neutral can cause all sorts of issues.  

  

Do I need to hook everything up in a different order of operations? Since my digi-stats appear to be toast I’m wondering if I need some sort of protection between the controller and t-stats to protect myself from myself - or from surges or lightning

  

Pic link below

https://imgur.com/a/imHXDQW

Jamie Hall

Trivial, but perhaps indicative -- the load side hot in that picture is wrapped the wrong way around the contact screw. Both neutral connections are wrapped wrong. On the other plug, it looks like you have a neutral and a hot connected to the same side of the plug -- a dead short.

From those pictures I can't possibly tell what other connections are wrong.

If you are protecting that circuit with a 30 amp fuse, all the 120 volt wiring needs to be 10 gauge wire.

If you are tapping into a circuit for a water heater, that's likely to be 240/120 -- are you sure you are tapping into the correct wires in that box?

I can tell you that the whole arrangement is somewhat dubious -- and a building inspector would never pass it.

gttra88

Here is a diagram. I did not have hot and neutral screwed on same side, but I realize what I did wrong. I’ll find another circuit to use that’s 15 amp

hot_rod

the screws on the receptacles are usually color coded and labeled. Confirm that you have them correct.

If the breaker pops when you plug into it, the short is downstream of the plug, in the control wiring.

Jamie Hall

I serously wonder if you really have 120/240 from the panel to the junction box to the hot water heater safety switch. If that cable is only 2 wire (presumably with ground), it may be the two sides of the 240 volt hot, with no neutral at all.

Most hot water heaters take 240 volts, and it isn't uncommon to wire them without the neutral, since they may not need it. The wires in the junction box should be clearly marked for that, but it's also not uncommon for the "white" wire -- which in such a wiring arrangement should have a black or red band on it -- to be left unmarked. I think you need to do some VERY careful testing before you proceed any further.

Ironman

Yeah, sounds like everything got hooked up to a 240v circuit instead of 120v.

HomerJSmith

You can confirm the voltage with an inexpensive digital volt meter that you can buy at Home Depot or Harbor Freight.

I think you would find that Jamie Hall's comment correct. You tapped into 220 V line.

Since Romex cable comes in White & Black wires for 2 conductor cable a water heater only needs a 2 conductor cable for 220 V. The white wire is not a grounded conductor, but a leg carrying 110V. A water heater is on a dedicated 30 amp 2 pole breaker, each pole supplying 110 V. That's how you get 220 V by adding them together. Electricians are suppose to mark a white wire carrying 110 V with a color other than green or, of course, white to indicate to someone later that that line is hot. Often that line isn't so marked. Always verify voltage, especially when in doubt.
You probably didn't just blow a fuse, but destroyed every thing that ran on 110 V on that circuit.

STEVEusaPA

HomerJSmith said:

You can confirm the voltage with an inexpensive digital volt meter that you can buy at Home Depot or Harbor Freight.

You can also kill yourself. Considering how dangerous this is, and the OP didn't have a clue, how much more do you all want to 'help'.

JUGHNE

In defense of electricians lack of marking the white to indicate that it is not a neutral.
That came into code enforcement perhaps 10 years ago.

It wasn't always done even after becoming code requirement.

Logic for not doing so:

One should realize that the WH is most likely 240 volts.....if you don't know that you should not be trying to wire anything.

If you see the white wire marked with Sharpie or such and don't know what that means....you should not be trying to wire anything.

I do mark whites as hot as it now is something checked by inspectors.
It is very important to mark the whites inside the CB panel as breakers may get moved around and it is easy to land that hot on the neutral bar........tough on something like the AC.

Looking at your workmanship in your pictures, I believe you need to have a separate circuit installed by a pro and have them complete the job........you are in over your head......

pecmsg

Orange SJ Cord?

please call an electrician your in over your head. 

HomerJSmith

As I recall some Romex came in an orange covering at one time. It looks like solid wire.
Romex is a Manufacture's trade name that became synonymous with MN cable.

pecmsg

HomerJSmith said:

As I recall some Romex came in an orange covering at one time. It looks like solid wire. Romex is a Manufacture's trade name that became synonymous with MN cable.

10G is orange
That makes sense with a 30A breaker!

Jamie Hall

HomerJSmith said:

As I recall some Romex came in an orange covering at one time. It looks like solid wire.
Romex is a Manufacture's trade name that became synonymous with MN cable.

The sheath of the 10/3 Romex I used the other day was orange. Pretty.

EBEBRATT-Ed

Now #10 is orange, #12 is yellow and #14 is white. But it has not always been this way, maybe 15 years? B4 that it could be any color