Wiring distribution and fusing questions

[pickles]

I am really confused about fusing and distribution of 50A service in my brew rig's control panel.
My equipment:
50A - 240V, 6AWG feed from GFCI Breaker
(6) 40A SSR
(2) 25A SSR
(1) 12v power supply
(2) 4500W element
(1) 3500W element
(2) 1/3 hp pumps (3A draw each)
(1) 4-pole distribution block (each input post has 6 output posts)
(2) 2-pole fuse holder
(10) single fuse holder

distribution block

fuse holder

single fuse holder

I don't understand why the distribution block accepts large wire sizes on the input side and reduces them to smaller gauge wire on the output without fuse protection. I need some help laying this thing out. What would be the best way to run 240v to each element's SSR, 110v to each pump's SSR and 110v to the power supply?

 

[Walker]

I don't understand why the distribution block accepts large wire sizes on the input side and reduces them to smaller gauge wire on the output without fuse protection.

It is perfectly acceptable to switch from a large gauge wire to a smaller gauge wire provided that the very first thing that the small wire connects to is an over-current device like a fuse or breaker.

This is called a "feeder tap" in national electric code and is A-OK to do.

So, run your large wire into the distro block, and then run smaller wires out of the distro block and directly into your fuses.

 

[Walker]

link to clarification of feeder taps:
http://ecmweb.com/nec/code-basics/electric_understanding_rules_feeder/

 

[cruelkix]

Pickles,

I would suggest laying out how YOU think it should go together and let others critique. No one knows exactly what you are trying to do. For example you have 6 x 40A ssrs being run off a 50 amp source. Thats a little confusing right there.

Also, do you have a 120v service or do you plan to use the 240v service and split it down to 120v for you pumps and such?

 

[Walker]

Pickles,

I would suggest laying out how YOU think it should go together and let others critique. No one knows exactly what you are trying to do. For example you have 6 x 40A ssrs being run off a 50 amp source. Thats a little confusing right there.

Also, do you have a 120v service or do you plan to use the 240v service and split it down to 120v for you pumps and such?

I understand the large number of high-rated SSRs fairly well. 25A SSRs are about the same price as 40A SSR's and there is no harm in using a 40A SSR to supply a lower load element.

However, I don't understand the use of SSRs for the pumps. Are you cycling the pumps during the mash or something? How many PIDS are involved here?

I think this thing might be overly complicated, to be honest.

 

[pickles]

Its controlled by a Brewtroller. I will not be cycling the pumps on and off, I got the 25A SSR for a few bucks so I figured I would use them for the pumps in lieu of mechanical relays. I'm sure its way over complicated but I am trying to use stuff I had on hand or industrial stuff purchased cheaply. I will be using one hot leg for my 110v equipment. The power cord is 6/4, so I will use the neutral and one hot leg.

Is it bad practice to use an SSR to operate a pump for a few hours?

 

[Sawdustguy]

Is it bad practice to use an SSR to operate a pump for a few hours?

Nate it's not bad practice. Use what ya got. It ya got SSR's go with them. I think Walker didn't realize you were building an automated setup.

 

[cruelkix]

I understand the large number of high-rated SSRs fairly well. 25A SSRs are about the same price as 40A SSR's and there is no harm in using a 40A SSR to supply a lower load element.

However, I don't understand the use of SSRs for the pumps. Are you cycling the pumps during the mash or something? How many PIDS are involved here?

I think this thing might be overly complicated, to be honest.

I would also have assumed thats why he went that route but I wanted to make sure.

I also stand by my statment of doing a wiring diagram for himself. Its the best way to learn and will give someone a great base to critique off of. Asking for help is one thing but asking for some one to draw upa wiring diagram for you can be a slightly time consuming effort, and in the long run wont teach him as much. I learned a TON when I did my all electric set up.

 

[Walker]

I think Walker didn't realize you were building an automated setup.

Correct. I didn't know this was automated like that.

 

[pickles]

I'll try to draw something up, I just don't know the symbols to use. I was just confused and needed an answer in order to begin drawing a layout. Thanks Walker for answering my question. I think Ohio-Ed has a schematic that represents something very similar to what I'm doing. I may pull it and see if his final plan still works for my scenario.

 

[Sawdustguy]

I'll try to draw something up, I just don't know the symbols to use. I was just confused and needed an answer in order to begin drawing a layout. Thanks Walker for answering my question. I think Ohio-Ed has a schematic that represents something very similar to what I'm doing. I may pull it and see if his final plan still works for my scenario.

Just do your best. There are no points deducted for accurracy. I am sure we will know what you mean.

 

[pickles]

Here is a quick schematic.

Any idea how I can post a PDF that exceeds the file size limit?

 

[cruelkix]

Its a little fuzzy, but from what I can make out, you have 2 SSR's per heating element. You only need 1.

How are you going to get down to 12v for the power supply?

 

[pickles]

I want to use two SSR per element so that stay. I need to provide the power supply with 110v, I don't remember the amperage off hand but I think it's 1.7A.

 

[cruelkix]

I want to use two SSR per element so that stay.

If you're set on it then go for it! Just out of curiosity, what benefit are you getting from it?

I need to provide the power supply with 110v, I don't remember the amperage off hand but I think it's 1.7A.

Ok thats good.

4500 + 3500 = 8000

8000/240 = 33.33333

33.33333 + 1.7 + 3 + 3 = 41.0333

Looks like you can run your pumps, controller and 1 x 4500w and 1 x 3500 and still be borderline 80% rule.

2 x 4500 = 9000

9000/240 = 37.5
37.5 + 1.7 = 39.2

Add the 6 for the pumps and it gets a little high @ 45.2.

 

[pickles]

One vs. Two SSRs has been discussed at length elsewhere but essentially it will allow me to turn off both hot legs of each element ( try are 240V). As for power consumption, I'll never have all elemnts on at one time.

 

[cruelkix]

One vs. Two SSRs has been discussed at length elsewhere but essentially it will allow me to turn off both hot legs of each element ( try are 240V).

I understand what it does, just dont understand the "why". Do you have the link to thread where it was talked about? I currently run my set up with only one on each so I'm curious.

As for power consumption, I'll never have all elemnts on at one time.

Yeah the above calcs only have you running two at one time. Three would be over for sure.

 

[pickles]

Not sure of the link off hand. If I were to have only one SSR on on one of the hot legs i could control the 240v device but when the SSR is "off" the other hot leg that isn't switched by a relay will still have 120v running through it. With two SSRs when it's off it's off. (assuming they don't fail or malfunction of course). It has led to some heated debates. I had plenty of SSRs available so I went a route I felt was safer. I'm also confident with my power usage and will be fine with 50A. My main question is about the wire sizes and fusing.

 

[Ohio-Ed]

Here is a quick schematic.

Any idea how I can post a PDF that exceeds the file size limit?

You can put the PDF in a zip file... the allowable zip file size is greater that PDF files... go figure.

If the file gets to big you have to host it somewhere else and link to it from HBT.

 

[TriangleIL]

I believe the dual SSR on each hot leg is a failsafe in case one of the SSRs fails. In the case where you always have a hot leg, it is possible the SSR on the controlled leg can fail, leading to both legs being energized. At least, I think thats what I read...

 

[Walker]

the 2-SSR thing is something people want for safety, too. with one SSR on one hot, the other hot is always live. It's nice to be able to completely and totally kill both hots.

I use one SSR on one hot for my element, controlled by the PID, but I have a large 2-pole contactor that I can shut off with a small switch and kill all the power.

 

[pickles]

Here is the CAD file zipped.

View attachment electric layout pickles june.zip

 

[Walker]

looks good to me. what is the 12V power supply for?

 

[pickles]

The Brewtroller requires 12V power supply, it will in turn activate the SSRs. My control panel (not shown) also has LEDs that require a DC power supply. I started wiring it earlier this evening.

 

[j_jones84]

Lurking and learning. Never thought of the distribution block or fuses... did you get these at auberins?

EDIT: Do most people fuse the SSR's and such?

 

[pickles]

Lurking and learning. Never thought of the distribution block or fuses... did you get these at auberins?

EDIT: Do most people fuse the SSR's and such?

I have learned that you need to fuse all devices to protect them from over current. Also, you need to ensure that if you have an over current situation that you have a way to protect the wire. Without a fuse, the wire can be subjected to excess current, get hot and melt. A fuse is simply a controlled weak point that fails before a catastrophe happens. It is definitely a necessity. I was confused on how to use the distribution block and fuses together, it seemed a bit contradictory. I have it figured out now I think. I purchased all of this stuff at a surplus house. Its all used or old stock, but really good stuff. My SSRs are all Crydom brand.

 

[j_jones84]

What is on the bottom right of the picture below the distribution block? That the grounding strip?

 

[pickles]

those are just extra distribution strips, i'll probably use one for the SSR wiring and one for ground

 

[j_jones84]

I noticed a lot of single fuse holders up top, did you decide not to put in the fuse holder block?

 

[pickles]

yep, I only had two fuse holder blocks, for a total of four fuses. I needed more and had lots of those, they have an o-ring built in that seals to the steel enclosure. They are very easy to replace, and I won't have to unlock the electrical enclosure to change fuses. It may not be practical but I was able to top notch stuff for a very low price.

 

[j_jones84]

Thanks for your responses. I just did a rough circuit diagram in paint for my setup... it looks horrible, did you use a wiring program or something to do your circuit?

 

[ClaudiusB]

Never thought of the distribution block or fuses...

j_jones84 having the wrong fuse or fuse holder for the job can be as bad as not having a fuse.
This picture shows all 5 Amp, 600 V AC fuses except the glass one 240 V AC, for different applications.
I am sure BrewBeemer still has nightmares seeing these fuses.

Cheers,
ClaudiusB

 

[pickles]

Having the wrong fuse or fuse holder for the job can be as bad as not having a fuse.
This picture shows all 5 Amp, 600 V AC fuses except the glass one 240 V AC, for different applications.
I am sure BrewBeemer still has nightmares seeing these fuses.

Cheers,
ClaudiusB

Your correct. The loose ones in my photo are 1A, they were in the holders when I got them. I have 2, 4, 5, 10, 15, 25 & 30A fuses in slo-blo and fast-acting. Those should work fine, unless there is something I don't know.

 

[Sawdustguy]

I understand what it does, just dont understand the "why". Do you have the link to thread where it was talked about? I currently run my set up with only one on each so I'm curious.



Yeah the above calcs only have you running two at one time. Three would be over for sure.

When these SSR's fail, they fail "ON". In other words when they fail they short, so if you only switch one leg and the switched leg fails the element is turned full on. If both legs are switched and one SSR fails, the element is still off. Kapish?

 

[ClaudiusB]

Your correct. The loose ones in my photo are 1A, they were in the holders when I got them. I have 2, 4, 5, 10, 15, 25 & 30A fuses in slo-blo and fast-acting. Those should work fine, unless there is something I don't know.

Sorry pickles this was just general info for j_jones84.

Your set up looks good.


Cheers,
ClaudiusB

 

[pickles]

ClaudiusB - No worries, I knew what you were refering to.

I am going to go ahead and try to finish my wiring this afternoon. Let me know if there are any issues I've missed.

Thanks all!

 

[Ohio-Ed]

ClaudiusB - No worries, I knew what you were refering to.

I am going to go ahead and try to finish my wiring this afternoon. Let me know if there are any issues I've missed.

Thanks all!

Pickles,
I'm no expert but your wiring diagram looks good to me.

One comment on the distribution blocks and fusing...
I know its a pain to work with larger wire, so I fully understand the desire to step down the size at the distribution block. The concern as I see it is in the smaller gauge wire between the distribution block and the fuse.

As a worst case scenario...
Let's say you have a double pole 50amp breaker and 6awg wire coming into the distribution block. Coming out of the block you run a 14awg wire to a fuse holder (with a properly sized fuse). If, for instance the 14awg going to the fuse holder came loose, and came in contact with the other hot leg of the 240, you'd have a short which would draw 50amps before the breaker tripped... the 14awg wire would get very hot and potentially catch fire.

Is this risk worth running larger wire? I have struggled with that question myself.

Ed

 

[pickles]

Ohio-Ed: this is exactly my concern. After seeing the comments here and doing some reading, it seems to be safe. I'm also using shrink tubing to help secure my connections. I can't see how it would be practical to use 6awg wire for all my connections to the fuses.

 

[pickles]

j_jones84: sorry I missed your question earlier; I just quickly drew it up in AutoCAD.

 

[cruelkix]

When these SSR's fail, they fail "ON". In other words when they fail they short, so if you only switch one leg and the switched leg fails the element is turned full on. If both legs are switched and one SSR fails, the element is still off. Kapish?

Gotcha. Thanks for the explination.

[argumentative]How do you know the one failed tho? Unless you are good about checking your equipment, when they are closed up in a case, how do you know when one is dead? You wont really know until they both die, so what's the point? Yeah Yeah, one is more likely to fail then 2, but these things arent really made to use the way we are using them. the controllers turn them on and off CONSTANTLY, like on/off once every second, unless your load setting is 0 or 100. They ARE going to fail, its just a matter of time. [/argumentative]

And are you sure they fail closed? When mine have no power to them they are open. I'm pretty sure you can buy different kinds. fail closed and fail open.