Wiring Diagram Help 200/30a 1 element 1 pump

[aarong]

Good day everyone! I'm looking for feedback on my attached diagram. It's for a 240/30a system. I did not include the wiring to my sensor for simplicity sake. I would really appreciate any feedback or advice. I'm not sure I have all the right fuses in the right place as well as the lights.

Goals:
1) Main power switch to panel when turned on a light will also turn on. This is my e stop
2) ssr with a pwm input signal running my 5500w heating element. When there is power to the element I want another light on.
3) Three way switch for pump. On,off, and controlled by a relay
4) standard 120v plug for controller and computer fan for the box
5) I want to use a plastic enclosure like the link below. I'm assuming I would ground everything to a ground bar that I mount in the box but wanted to confirm.

Gratury Junction Box, Hinged Cover Stainless Steel Latch IP67 Waterproof Plastic Enclosure for Electrical Project Includes Mounting Plate and Wall Bracket 220×170×110mm (8.6"×6.7"×4.3") Gratury Junction Box, Hinged Cover Stainless Steel Latch IP67 Waterproof Plastic Enclosure for Electrical Project Includes Mounting Plate and Wall Bracket 220×170×110mm (8.6"×6.7"×4.3") - - Amazon.com

Thank you!!!

 

[RufusBrewer]

Many ways to slice and dice your wish list. Much will depend on what you budget, where you choose to source your components and your level of being comfortable with electrical circuits

1) Put a light in parallel with the rest of the rest of your system. On this board, Estop means different things to different people. The most basic Estop is a mastewr switch that de-engerises everything in the sytem. Are you thinking about a mushroom (slap down) style of Estop?

2) A lamp that is in parallel with the heating element (but before teh SSR) describes what you are require.

3) Need more information on this. What kind of relay? Does the relay control speed of the pump do ON and pump Relay On.

4) Buy a 120 VAC fan or a DC power supply and matching DC Fan

5) This is one way to do it and nothing wrong with this design. Hint: Do not go cheap. Buy a bigger box than you think you need. If nothing else, it will make working in the box and building you system easier. Also provide space for system enhancements.

Do not forget to provide a GFCI.

 

[aarong]

Many ways to slice and dice your wish list. Much will depend on what you budget, where you choose to source your components and your level of being comfortable with electrical circuits

1) Put a light in parallel with the rest of the rest of your system. On this board, Estop means different things to different people. The most basic Estop is a mastewr switch that de-engerises everything in the sytem. Are you thinking about a mushroom (slap down) style of Estop?

2) A lamp that is in parallel with the heating element (but before teh SSR) describes what you are require.

3) Need more information on this. What kind of relay? Does the relay control speed of the pump do ON and pump Relay On.

4) Buy a 120 VAC fan or a DC power supply and matching DC Fan

5) This is one way to do it and nothing wrong with this design. Hint: Do not go cheap. Buy a bigger box than you think you need. If nothing else, it will make working in the box and building you system easier. Also provide space for system enhancements.

Do not forget to provide a GFCI.

Thank you for the info. I was not very explicit in my post but I attached an image with the wiring diagram. The goals was to help explain the wiring diagram. Please let me know if the attached image is not showing.

 

[RufusBrewer]

The schematic is pretty much correct. A few comments:

You do not detail the controller for the heating element SSR and pump relay. SSR is is pretty forgiving in terms of what it draws from a control system. Amusing your pump relay is a mechanical relay with a coil and contacts, make sure the output of the controlling device can handle the coil as a load.

The 30 amp fuse in line with the heating element will not do anything. The source p0wer 120 VAC circuit is 15 or 20 amps, that breaker will pop before the 30 amp fuses opens.

Typically an SSR go in line with the hot leg.

The lamp for the element will get the same signal as the element. Depending on the lamp this might be a problem. I am not familar with lamps to say for sure. Buy tis will probably go dim/bright and/or flash on and off

I assume the pump switch is a 3 position switch where center is off. The tech sheet spec is typically ON-OFF-ON.

The element in you schematic 5,500 watts @ 240 VAC, using a 120 VAC will give you:

120 VAC
1,375 watts
11.5 amps
10.5 ohm

Make sure your AC circuit can handle that. Are there any other devices on the same breaker? E.g. Refriderators, washing machines, lamps, TVs AC sockets etc. If so, include them in your breaker budget.

 

[aarong]

Thank you so much for the feedback:

I plan on installing a 240v 30 amp breaker. So it'll be a dedicated system with no other appliances.

The heating element is 5500 watts at 240 volt which should draw around 23 amps

Great point on the light for the heating element. I want some type of indicator that it's powered but this would have to be rated for at least 30 amps

I'm building my own ssr and relay controller using a raspi or esp32 controller with gpio pins. The relay is a simple on and off. The ssr is run on PWM I still want to figure out the signal frequency.

The 240 volt input has two hot lines. I picked one randomly to go through the ssr. Do I need to pick a certain one? The heating element has two hot lines going into it as well as a ground.

I really appreciate the feedback! I don't want to get hurt when I fire this thing up.

 

[doug293cz]

The schematic is pretty much correct. A few comments:

You do not detail the controller for the heating element SSR and pump relay. SSR is is pretty forgiving in terms of what it draws from a control system. Amusing your pump relay is a mechanical relay with a coil and contacts, make sure the output of the controlling device can handle the coil as a load.

The 30 amp fuse in line with the heating element will not do anything. The source p0wer 120 VAC circuit is 15 or 20 amps, that breaker will pop before the 30 amp fuses opens.

Typically an SSR go in line with the hot leg.

The lamp for the element will get the same signal as the element. Depending on the lamp this might be a problem. I am not familar with lamps to say for sure. Buy tis will probably go dim/bright and/or flash on and off

I assume the pump switch is a 3 position switch where center is off. The tech sheet spec is typically ON-OFF-ON.

The element in you schematic 5,500 watts @ 240 VAC, using a 120 VAC will give you:

120 VAC
1,375 watts
11.5 amps
10.5 ohm

Make sure your AC circuit can handle that. Are there any other devices on the same breaker? E.g. Refriderators, washing machines, lamps, TVs AC sockets etc. If so, include them in your breaker budget.

Agree that design is functional and safe, as long as fed by a GFCI breaker.

OP's input power is 30A @ 240V, not 120V.

The 30A fuses are not necessary, since the circuit is already protected by a 30A breaker.

My other comments to OP:

Using lighted switches can save you some front panel space.

The element firing light is wired correctly if you want to know when the element is actually receiving power. It will also tell you if the SSR gets stuck in the "on" mode. The light on the SSR itself is useless for this, as it only lets you know that the SSR is receiving a control signal.

You could eliminate another fuse by splitting the hot bus into high current and low current segments and placing a 10A fuse between the segments.

Brew on

 

[aarong]

Agree that design is functional and safe, as long as fed by a GFCI breaker.

OP's input power is 30A @ 240V, not 120V.

The 30A fuses are not necessary, since the circuit is already protected by a 30A breaker.

My other comments to OP:

Using lighted switches can save you some front panel space.

The element firing light is wired correctly if you want to know when the element is actually receiving power. It will also tell you if the SSR gets stuck in the "on" mode. The light on the SSR itself is useless for this, as it only lets you know that the SSR is receiving a control signal.

You could eliminate another fuse by splitting the hot bus into high current and low current segments and placing a 10A fuse between the segments.

Brew on

This is great thank you so much!

It makes sense that the 30A fuse is useless with the circuit breaker. I am planning on installing a gfci one. Luckily the outlet will be a foot from the panel so shouldn't be too hard.

I like the lighted switch idea and will use that.

I like the idea of splitting the hot bus to high and low current

Thank you so much!

 

[doug293cz]

Thank you so much for the feedback:

I plan on installing a 240v 30 amp breaker. So it'll be a dedicated system with no other appliances.

Be sure it's a GFCI breaker, or put a standalone GFCI on the control panel input.

The heating element is 5500 watts at 240 volt which should draw around 23 amps

Great point on the light for the heating element. I want some type of indicator that it's powered but this would have to be rated for at least 30 amps

The element is enabled to receive power whenever the main power switch is on, and this will be indicated by the main power lamp. The lamp, as you currently have it wired will light whenever the SSR is actually delivering power to the element (i.e. an "Element Firing" lamp.) Since the lamp is wired in parallel with the element, rather than in series, it will not carry the same current as the element, but will be subjected to the same voltage differential. The lamp just needs to be rated for 240V - no need to worry about current rating.

I'm building my own ssr and relay controller using a raspi or esp32 controller with gpio pins. The relay is a simple on and off. The ssr is run on PWM I still want to figure out the signal frequency.

The 240 volt input has two hot lines. I picked one randomly to go through the ssr. Do I need to pick a certain one? The heating element has two hot lines going into it as well as a ground.

Doesn't matter which hot you choose to switch with the SSR.

I really appreciate the feedback! I don't want to get hurt when I fire this thing up.

Edit: Sorry for reanswering things that were updated while I was typing,

Brew on

 

[RufusBrewer]

I will strongly recommend putting the GFCI in the breaker panel, if practical. This will give you the maximum protection against mishap and misadventure.

If you put the GFCI breaker in the control box, you do not have protection from the AC socket to your box. Granted, the most likely place you are going to have an issue is from the controller out. But more protection the better and when it comes to safety, error on the side of safer.

 

[aarong]

I will strongly recommend putting the GFCI in the breaker panel, if practical. This will give you the maximum protection against mishap and misadventure.

If you put the GFCI breaker in the control box, you do not have protection from the AC socket to your box. Granted, the most likely place you are going to have an issue is from the controller out. But more protection the better and when it comes to safety, error on the side of safer.

Will do thank you

 

[aarong]

So I have another question. Instead of using a relay for my pump(on/off) I plan to use a SSR so I can control the pump speed. The pump is a 120v March pump.

1)For an SSR what frequency do you use for the PWM input for a heating element and for the Pump?

2)Any recommendations on a good SSR brand that won't blow up on me? I had a friend have his cheap SSR blow up on him and want to avoid this?

I read alot of mixed info.

 

[RufusBrewer]

I recommend that you research and confirm that an SSR is an appropriate way to control a pump.

A pump motor is different from a light bulb filament. A complete explanation to this issue requires knowledge that I do not have.

I have a March style pump and it gets it's 100% 120 VAC. I throttle the Gallons Per Minute via ball valve on the output.

 

[aarong]

I recommend that you research and confirm that an SSR is an appropriate way to control a pump.

A pump motor is different from a light bulb filament. A complete explanation to this issue requires knowledge that I do not have.

I have a March style pump and it gets it's 100% 120 VAC. I throttle the Gallons Per Minute via ball valve on the output.

I didn't think of that thank you! I'll have to switch to a motorized ball valve. Thank you

 

[RufusBrewer]

I didn't think of that thank you! I'll have to switch to a motorized ball valve. Thank you

Just to be clear. I am not saying that you should not or cannot do it. Just advising that you verify if you can.

 

[doug293cz]

So I have another question. Instead of using a relay for my pump(on/off) I plan to use a SSR so I can control the pump speed. The pump is a 120v March pump.

1)For an SSR what frequency do you use for the PWM input for a heating element and for the Pump?

2)Any recommendations on a good SSR brand that won't blow up on me? I had a friend have his cheap SSR blow up on him and want to avoid this?

I read alot of mixed info.

Motor speed control is out of my wheelhouse, so can't advise you there.

Most of the SSRs used in brew control panels are what are known as "zero crossing" turn on. This means that no matter when you send the turn on signal, it won't actually turn on until the AC voltage waveform goes to zero (this minimizes electrical noise), and then after the trigger signal is removed, the SSR stays on until the current flowing thru it goes to zero. This means you need to have a PWM cycle time of about 1 - 2 seconds minimum. With 60 Hz AC (120 half cycles/sec), you will have 121 discrete power settings with a 1 sec cycle time (0 to 120 half cycles per trigger pulse, depending on pulse width.)

Avoid buying Fotek SSRs from anyone but an authorized distributor (never buy Foteks from Amazon, Ebay, etc.) Many of the cheap Foteks are counterfeit and made with underrated components. Do not buy "no-name" SSRs. If you really want to be conservative, buy a brand name like Crydom.

Brew on

 

[aarong]

I'm almost finished with the project. Just had a quick question with wiring the 220 v heating element. My diagram has an always on hot line and the second hot line is through the SSR. Any issues with this. I assume it needs a complete circuit to heat up so if my SSR is off and the always hot line is on it will not heat up. Am I way off?

 

[bruce_the_loon]

I'm almost finished with the project. Just had a quick question with wiring the 220 v heating element. My diagram has an always on hot line and the second hot line is through the SSR. Any issues with this. I assume it needs a complete circuit to heat up so if my SSR is off and the always hot line is on it will not heat up. Am I way off?

No issues, that is the way it is supposed to be.

 

[aarong]

ok great!

 

[RufusBrewer]

I'm almost finished with the project. Just had a quick question with wiring the 220 v heating element. My diagram has an always on hot line and the second hot line is through the SSR. Any issues with this. I assume it needs a complete circuit to heat up so if my SSR is off and the always hot line is on it will not heat up. Am I way off?

FYI With American 220 VAC, the two legs are equal. Equal in the idea that they have no conventional polarity, no plus, no minus no ground, no neutral.

Having said that, do not take that to mean the pay have no voltage. Both legs have voltage, plenty of power. A voltage level the same as your regular 120 VAC that you plug you lamps and TV into. So treat them both with great respect and safety.

When you switch 220V On or Off, or use a SSR, etc - you have the choice of which leg to place the switch or SSR.

While I cannot really explain why. But any design I might do, I would choose one of the two legs and place my switches, SSR etc consistently in the same leg.

 

[bruce_the_loon]

FYI With American 220 VAC, the two legs are equal. Equal in the idea that they have no conventional polarity, no plus, no minus no ground, no neutral.

Having said that, do not take that to mean the pay have no voltage. Both legs have voltage, plenty of power. A voltage level the same as your regular 120 VAC that you plug you lamps and TV into. So treat them both with great respect and safety.

When you switch 220V On or Off, or use a SSR, etc - you have the choice of which leg to place the switch or SSR.

While I cannot really explain why. But any design I might do, I would choose one of the two legs and place my switches, SSR etc consistently in the same leg.

While I come from a 240V single-phase environment, I can suggest that like a single-phase design where the switchgear is on the the live leg and the simple wiring for the neutral avoid most switching (except for isolators and contactors), the same design is kept mostly for a 120/120 split phase for simplicity sake, effectively treating the second hot as a neutral for the 240V devices without loss of safety. While powering 120V devices like pumps could be place across either hot leg to neutral and balance the load better, the relative size of most 120V loads (pumps, valves, motors) to the heating element draw won't significantly unbalance the system and using them on one hot only simplifies the design.

However I have to wonder whether balancing two 120V heating elements would benefit the split-phase system the way balancing in three-phase does. Certainly the benefit of putting half the current on each hot would reduce heating on the individual conductors, but with the shared neutral carrying the entire current load would probably undo that benefit. Do the effects of imbalance on a three-phase system extend to split-phase? Inquiring minds and all that.

 

[doug293cz]

FYI With American 220 VAC, the two legs are equal. Equal in the idea that they have no conventional polarity, no plus, no minus no ground, no neutral.

Having said that, do not take that to mean the pay have no voltage. Both legs have voltage, plenty of power. A voltage level the same as your regular 120 VAC that you plug you lamps and TV into. So treat them both with great respect and safety.

When you switch 220V On or Off, or use a SSR, etc - you have the choice of which leg to place the switch or SSR.

While I cannot really explain why. But any design I might do, I would choose one of the two legs and place my switches, SSR etc consistently in the same leg.

This is incorrect. 240V split phase legs do have polarity, and that switches between positive and negative (relative to ground) 120 times per second. The two legs have opposite polarities and equal voltage differences to ground at all times. There is also a neutral, which is near ground potential. Any current imbalance between the two phases flows in the neutral. Here's a diagram of the two phases relative to each other and ground:

Note that the instantaneous voltage on a phase varies between -170V and +170V, but if averaged over time (using the root mean square [RMS] method) the nominal voltage is 120V. Between the two phases, the instantaneous voltage difference varies between 0 and 340 volts, and the RMS average is 240V. RMS averaging is used because an AC power source @ 120V RMS delivers the same time averaged power as a DC 120V power source when driving equal impedance loads.

You are correct that modulating power with an SSR or switch on a single leg to a 240V load does not remove voltage from the load. This is why you should always have a double pole switch or contactor between the power source and load, as this is what allows you to actually de-energize the load.

Brew on

 

[doug293cz]

While I come from a 240V single-phase environment, I can suggest that like a single-phase design where the switchgear is on the the live leg and the simple wiring for the neutral avoid most switching (except for isolators and contactors), the same design is kept mostly for a 120/120 split phase for simplicity sake, effectively treating the second hot as a neutral for the 240V devices without loss of safety. While powering 120V devices like pumps could be place across either hot leg to neutral and balance the load better, the relative size of most 120V loads (pumps, valves, motors) to the heating element draw won't significantly unbalance the system and using them on one hot only simplifies the design.

However I have to wonder whether balancing two 120V heating elements would benefit the split-phase system the way balancing in three-phase does. Certainly the benefit of putting half the current on each hot would reduce heating on the individual conductors, but with the shared neutral carrying the entire current load would probably undo that benefit. Do the effects of imbalance on a three-phase system extend to split-phase? Inquiring minds and all that.

No, in a 240V split phase system the "second" hot leg is not like a neutral. All switching that is intended to de-energize (remove voltage and current) needs to switch both legs, since both legs can deliver power. In a single phase system, neutral cannot deliver power, so it does not need to be switched. Using a switch or SSR on a single leg in a 240V system will interrupt power in the load, it will not de-energize the load. Thus power modulation can switch a single leg, but safety disconnect requires switching both legs (and using an air gap, rather than semiconductor switch.)

If you have two loads, one on each leg of a split phase power source, then most of the current flows thru the hot legs. The only current flowing in the neutral is the difference in the currents flowing thru each load. If you have two heating elements with equal resistance, each with one side connected to a different hot leg, and the other sides connected to a common neutral, the currents in each element will be equal, and the current in the neutral will be 0.

Brew on

 

[RufusBrewer]

This is incorrect. 240V split phase legs do have polarity, and that switches between positive and negative (relative to ground) 120 times per second. The two legs have opposite polarities and equal voltage differences to ground at all times. There is also a neutral, which is near ground potential. Any current imbalance between the two phases flows in the neutral. Here's a diagram of the two phases relative to each other and ground:

View attachment 761526

Note that the instantaneous voltage on a phase varies between -170V and +170V, but if averaged over time (using the root mean square [RMS] method) the nominal voltage is 120V. Between the two phases, the instantaneous voltage difference varies between 0 and 340 volts, and the RMS average is 240V. RMS averaging is used because an AC power source @ 120V RMS delivers the same time averaged power as a DC 120V power source when driving equal impedance loads.

You are correct that modulating power with an SSR or switch on a single leg to a 240V load does not remove voltage from the load. This is why you should always have a double pole switch or contactor between the power source and load, as this is what allows you to actually de-energize the load.

Brew on

You are conflating phase and polarity.

American 220 VAC is not polarized. Polarized means you cannot swap the orientation of the two (or more) poles.

The neutral pole is irrelevant to an 220 VAC circuit.

Neither leg is properly described as positive or negative. Each leg is 180 deg out of phase with respect to the other. The amplitude is derived by the difference between the poles. Both are of equal amplitude when reference to neutral or ground.

You are correct to make the point that the best practice (for safety reasons) to use an On/Off switch and switch off/de-energize both poles.

 

[mrveeno]

Concur with Rufus. And just so you understand, circuit breakers are not there to protect any devices, they are there to protect the wiring. The GFI is there to protect you.

 

[RufusBrewer]

A circuit breaker cannot protect a device. Anything you put in a breaker must draw less than the breaker trip point. A device that is designed to draw 1 amp but is damaged upon drawing 2 amps, a 15 amp breaker will be happy to supply 2 amps as the device smokes into oblivion.

 

[bruce_the_loon]

Frouds Law: A transistor protected by a fast acting fuse will protect the fuse by blowing first.