Electric Wiring Help

Hey everybody,
I need some help with some pretty simple wiring questions. I'm using two 1500W Heating elements on two different 20A circuit breakers via non-GFCI outlets.

Background/Assumptions:
On outlet A, I'm hooking up one heating element and a march pump. Both probably won't be on at the same time (at least most of the time). March pumps supposedly operate at 1.4A, and I will be installing a dimmer switch to vary the power to it. I'm also thinking of installing a switch to bypass the SSR so I can turn it on manually (3-way switch I guess, not drawn). So... heating element (1500W/120V + 1.4A = 13.9A)

On outlet B, I'm hooking up the other heating element and the BCS-460. I don't know how much power the BCS-460 will pull, but I don't think it will be much, especially compared to the march pump.

The BCS-460 will be controlling the SSRs attached to the heating elements and march pump. Between the heating element and SSR, I will have a kill switch... essentially I have to "arm" the heating elements before they can be used.

I may eventually add solenoid valves into the mix, but they're a bit pricey. At most three would be on at any one time and they draw a little less than 0.2A each (@120V), so 0.6A extra. These would probably go on Outlet B.

Questions:
Since I'm plugging these into the 20A (non-GFCI) outlets, should I bother with getting 20A GFCI outlets for inside my box, or should I just go with 15A GFCI outlets? (I'm leaning towards the 15A ones).

-Answered: Wouldn't I need a 20A cable to go from my control box to the wall outlet (which probably isn't rated for 20A, but is on a 20A breaker)? EDIT: If I went with 20A GFCI Box outlets I'd need a 20A cable.

New Question: Is there a way to check the outlet if it is capable of 20A? Probably by taking the cover off and looking for something?

Answered: Is it ok to assume that my current draw won't exceed 15A given the highest draw would be from the heating element + march pump (13.9 < 15)? No it's not

Answered: Is it ok to run the march pump off a dimmer switch like that? I was thinking of a regular light dimmer switch, since I know it can handle 120V vs a potentiometer. It might not work the way I think it does. The BCS and SSR can probably give a PWM signal to the motor to handle adjusting the speed.

Answered: Could I run the heating elements off a dimmer switch to effectively change their power? (would give me more control, could automate this using a servo later) Need to get a big enough dimmer switch, but I probably will just relay on the BCS turning the elements on and off anyways. Less hassle that way.

Answered: For grounding: Does everything share the same ground (even the two separate outlets)? Is there any danger in having a "universal" ground?

New Question: For the cable between the wall and my control box. I'd like something like a computer desktop power cable, I believe they use what's called IEC connectors (?) Is there a good source for these that are 20A rated?

New Question: On the inside of the box, at the connector, I plan on wiring it to GFCI outlets (using the appropriate gauge wire) for inside the box to connect the components to... Anything wrong with that?

Is there anything clearly wrong with my proposed setup?

I'm fairly confident I can go with the 15A route, but wanted to double-check before I started ordering supplies.
Edit 1: Now I'm leaning more towards the 20A route, going to check the outlets when I get home.
Edit 2: Due to my apartments wiring, I'm going to go with a dual 15A setup and set it up so that the March pump and corresponding heating element can NOT be on SIMULTANEOUSLY.

There's a lot of questions in here, but I'll try to hit a few.


Current draw... never assume anything about what your current draw will or will not exceed. A short in your system can make the current draw shoot up to infinity. Also, even if there is no short and things are working fine, an electric motor (in your pump) will have a higher amp pull when first turned on, which will then settle back down. If the pump normally operates at 1.4A, the initial current when you flip it on will be greater than 1.4A.

15A vs 20A.... you would be best off with 20A cable, outlets, etc. I am willing to bet that that the outlet on your wall is capable of handling 20A if it is being supplied by a 20A breaker. If it's NOT capable of handling 20A, then your house wiring needs to be looked at and corrected because it's violating building code and is a fire hazard.

Ground... ultimately, the ground wires on every outlet in your house are tied together. Ground is ground.

Dimmer switch... Probably not going to work like you want. Might make the motor behave poorly (supplying it with a voltage lower than 110V might cause it to actually not run at all.) I don't think you can even find a dimmer that would work for the super-low-resistance heating element. The ideal way to control both of these things is with Pulse Width Modulation.... rapid on and off switching of the power to the things to get the level of operation that you want. The BCS and your SSRs will probably do this for you.

13.9A on a 15A circuit is pushing the limit and you may have a breaker frequently tripping, even though it is less than 15A. The current drawn, ambient temps, install issues all go into the equation. You want to have about 80% of max amps used on a circuit for safety. I would go with 20A for that.

As far as hooking up a dimmer for the heating element, you MUST get a dimmer rated for 2000W. Heating elements draw more current when cold. Safety is a big issue here. Maybe a better way to control it would be a thermostat. Either way it must be able to handle 1500W.

As far as everything sharing a universal ground, all grounds in the circuit should go back to the ground bus bar. Wiring diagrams will show you how to do this.

If you wire a non-GFCI receptacle to the GFCI load terminals, that receptacle will be protected through the GFCI. Of course, you can GFCI a GFCI or you can pigtail and have each GFCI independent. Make sure you do this correctly.

Thanks for the help both of you! I edited my first post in case people come back, and I added some new questions.

triethylborane said:

Of course, you can GFCI a GFCI or you can pigtail and have each GFCI independent. Make sure you do this correctly.

Click to expand...

I understood the rest of your comment except this part. If I'm reading it right you mean if I DID have a GFCI outlet, I could plug a second GFCI cord/outlet to it?

Sorry, but I'm working and don't have time for an extended post. One thing you need to scratch, the dimmer on the March pump. That is a very bad idea. It is a magnetically-coupled impeller pump, so you control flow rate via a valve on the OUTFEED-side of the pump. You can completely close it off and the pump is not harmed in any way. The only way to properly control pump speed is via PWM control without losing the power rating of the pump motor. This is beyond the scope of your question and is not desirable anyway. As I said, just valve it and call it good.

bull8042 said:

The only way to properly control pump speed is via PWM control without losing the power rating of the pump motor. This is beyond the scope of your question and is not desirable anyway. As I said, just valve it and call it good.

Click to expand...

Yup. Ball valve on pump output to control the flow.

PWM for the heating element should be possible via the BCS (but I'm not familiar with the BCS and am making an assumption about the features.)

If your outlet is fed by 12 gauge wire, it is rated for 20 amps. You can replace the breaker and receptacles with 20 amp versions. While you're at it, replace the 15 amp breaker with a 20 amp GFCI breaker (Note: NOT an AFCI - There's a difference, and you want a GFCI) 12 gauge wire will either be labeled as such, or have a yellow outer jacket. Some older 12 gauge wire used to have a white jacket, but that was a loooong time ago
Don't put GFCIs in your control panel. I know you can, and that a lot of folks here have but a GFCI only protects stuff after it in the circuit. What happens if you have an issue inside the panel?!? No ground fault protection there!
Install a GFCI breaker, or replace the receptacle with a 20 amp GFCI.

If your outlets are wired with 14 gauge, you're screwed.

How far are you going to be brewing from your main panel? You could always install a 220v receptacle at or near the panel, and get out the "220v extension cord" when you want to brew...

That's my plan. I have a 50 amp 220v receptacle at the sub panel in the garage, but I'll be brewing on the other side of the garage, or outside. Then it's 25 or 50' of 50 amp rated SJOOW cable

I'm on my phone in the metro, but I definitely won't use a dimmer. The breaker is far enough away that it wouldn't be feasible, and I live in an apartment building so I probably can't switch out breakers myself without them getting pissy. Ive also already bought the heating elements and don't want to switch to 220 (want to make it semi portable)

I don't know if the BCS can do PWM stuff, but I know it can control the elements by turning them on and off... Just don't know if it's PWM fast. I don't think so... It should be waiting for me at home.

Will post more later, thanks for all the help!

OEHokie said:

I'm on my phone in the metro, but I definitely won't use a dimmer. The breaker is far enough away that it wouldn't be feasible, and I live in an apartment building so I probably can't switch out breakers myself without them getting pissy. Ive also already bought the heating elements and don't want to switch to 220 (want to make it semi portable)

I don't know if the BCS can do PWM stuff, but I know it can control the elements by turning them on and off... Just don't know if it's PWM fast. I don't think so... It should be waiting for me at home.

Will post more later, thanks for all the help!

Click to expand...

I understand...
The BCS will drive the SSRs that drive your elements. It's a computer integrated quad PID

Dang... just figured some stuff out about my kitchen, and it's not good.

First some pictures:

Note, this is an old building. It looks to be pretty heavy gauge stuff... but it does have a white casing. If I had to guess, I'd say this building was built in the 70s or 80s, but honestly, I have NO idea.




Next: Breakers 10 and 12 are the kitchen ones. One of these also has the fridge on it, so I'm basically screwed there. Definitely can't use that one for 20A brewing because I'm sure the fridge takes up a lot. The other breaker in the kitchen doesn't really have anything on it, which is good.

The microwave and disposal plug are inaccessible. There are other 15A breakers around that I could use... so I'm going to "suggest" to myself that I build a two breaker, 15A system... and limit the March pump so that it and the heating element can NOT be on simultaneously (so, a switch that determines which can be on). This forces me to be "less automated", and I sorta which I had looked up some of this stuff before... oh well, live and learn.

SweetSounds said:

Don't put GFCIs in your control panel. I know you can, and that a lot of folks here have but a GFCI only protects stuff after it in the circuit. What happens if you have an issue inside the panel?!? No ground fault protection there!
Install a GFCI breaker, or replace the receptacle with a 20 amp GFCI.

Click to expand...

You might have misunderstood what I meant, but maybe you didn't... everything inside my panel would be connected to the GFCI outlets in my panel. So the wires coming into the box (from the wall outlets) would go straight to the GFCI outlets inside the panel... and everything then connects to those outlets. So if something happens inside the panel, it'd trip the GFCI outlets and not make it out to the breaker (ideally).

OEHokie said:

Next: Breakers 10 and 12 are the kitchen ones. One of these also has the fridge on it, so I'm basically screwed there. Definitely can't use that one for 20A brewing because I'm sure the fridge takes up a lot. The other breaker in the kitchen doesn't really have anything on it, which is good.

Click to expand...

You should be able to check the current draw from your fridge as it should be on a panel eith on the back (a apin if its in a recess) or somewhere on the front cover by the door when closed, mine are both at the bottom front of the body. AFAIK fridges don't pull that much (1-2A bassically just another small motor) when running but maybe if it started up when you were brewing it might trip, maybe. Check it out before limiting youself, you could also just turn off you fridge when brewing - whats more important, beer or food?

Would there be anything wrong with having using both breakers... i.e. The half with the heating element/march pump on a 20A GFCI plug and the other half with the heating element/BCS-460 on the 15A GFCI plug... with a common ground?

Not sure if I'll do it that way, but good to know my options, I'll probably still limit the element/pump to not run at the same time and be safe like that until I move into a different apartment (won't be here forever).

OEHokie said:

Would there be anything wrong with having using both breakers... i.e. The half with the heating element/march pump on a 20A GFCI plug and the other half with the heating element/BCS-460 on the 15A GFCI plug... with a common ground?

Not sure if I'll do it that way, but good to know my options, I'll probably still limit the element/pump to not run at the same time and be safe like that until I move into a different apartment (won't be here forever).

Click to expand...

Not a problem at all, but you may have to segregate the grounds in your panel to the circuit they feed. It's worth a shot bonded, because all it will do is trip the GFI if there is a ground leak out the wrong circuit.

A 15 amp breaker with no other load will only deliver 1800 watts. This means you cannot even use a 2000 watt element. You'll have to go with a 1500. It'll work, but you might need 2 of them to get 5 gallons to a boil in any reasonable amount of time.

Remember, a PID (BCS in this case) controls the heat by switching the element fully on, for a percentage of time. IOW if the period is 2 seconds, and it's driving "50%" heat, the element is 100% on, for 1 second, and 100% off for 1 second.

SweetSounds said:

Not a problem at all, but you may have to segregate the grounds in your panel to the circuit they feed. It's worth a shot bonded, because all it will do is trip the GFI if there is a ground leak out the wrong circuit.

A 15 amp breaker with no other load will only deliver 1800 watts. This means you cannot even use a 2000 watt element. You'll have to go with a 1500. It'll work, but you might need 2 of them to get 5 gallons to a boil in any reasonable amount of time.

Remember, a PID (BCS in this case) controls the heat by switching the element fully on, for a percentage of time. IOW if the period is 2 seconds, and it's driving "50%" heat, the element is 100% on, for 1 second, and 100% off for 1 second.

Click to expand...

I am using 1500W elements, never said I was using a 2000w

Edit: Elaborating because that last post was from my phone... My plan is two use two 1500W elements on different breakers (one on each). Thanks for the comment!