Question about stepping down wire size for PID

[HossTheGreat]

I have 240v coming into my control panel, and will probably need to step down the wire from 10 gauge to 14 to my PID. What's the best way to do this? An in-line fuse rated at 5 amps or so? If I'm bringing both hot legs into the PID, I assume I'll need to run both into separate fuses to protect the smaller gauge wire going into the PID. Is this the best way, or is a better way to accomplish this?

 

[CorgiBrew]

I have 240v coming into my control panel, and will probably need to step down the wire from 10 gauge to 14 to my PID. What's the best way to do this? An in-line fuse rated at 5 amps or so? If I'm bringing both hot legs into the PID, I assume I'll need to run both into separate fuses to protect the smaller gauge wire going into the PID. Is this the best way, or is a better way to accomplish this?

Maybe I'm misunderstanding, but why would you bring both legs into your PID? The PIDs used for homebrewing typically run on 120v, so they only need one leg. There are some excellent wiring tutorials here. Most folks run the inbound 240v through a distribution block, which lets you step down to appropriate voltages and wire gauges as necessary to your plan. You can then put a fuse inline between the distribution block and the PID to protect te electronics.

 

[HossTheGreat]

Maybe I'm misunderstanding, but why would you bring both legs into your PID? The PIDs used for homebrewing typically run on 120v, so they only need one leg. There are some excellent wiring tutorials here. Most folks run the inbound 240v through a distribution block, which lets you step down to appropriate voltages and wire gauges as necessary to your plan. You can then put a fuse inline between the distribution block and the PID to protect te electronics.

I have an auber pid, which supports 240v input. I'm not feeding any 120v devices right now in my control panel, so I was just planning on bringing the 240 directly in. I suppose I could wire it up with 120v but would still need to step down the wire size.

 

[stevehaun]

Yes, you will need to fuse both limbs of the 240 vac going to your pid.

 

[jkarp]

14 gauge is massive overkill. The PID uses less than 2 Watts so 20 gauge is plenty. A 5A fuse would be useless too. If something went wrong, the PID would be long dead and crispy before a 5A fuse blew. At 240V, you'd probably want a 10-15mA fuse, and no, you don't need to fuse both legs to protect the PID (see the Auber instructions for your PID - they have wiring diagrams).

 

[HossTheGreat]

14 gauge is massive overkill. The PID uses less than 2 Watts so 20 gauge is plenty. A 5A fuse would be useless too. If something went wrong, the PID would be long dead and crispy before a 5A fuse blew. At 240V, you'd probably want a 10-15mA fuse, and no, you don't need to fuse both legs to protect the PID (see the Auber instructions for your PID - they have wiring diagrams).

Make's sense. I guess I was thinking more along the lines of protecting the wire from overcurrent, not specifically the PID. I was doing some reading on Kal's site, where he has a 7A fuse protecting the #14 wire feeding his PID which is where I got the idea.

 

[jkarp]

Make's sense. I guess I was thinking more along the lines of protecting the wire from overcurrent, not specifically the PID. I was doing some reading on Kal's site, where he has a 7A fuse protecting the #14 wire feeding his PID which is where I got the idea.

Well, a 15mA fuse is going to protect your wire as well as your PID.

 

[Sawdustguy]

Make's sense. I guess I was thinking more along the lines of protecting the wire from overcurrent, not specifically the PID. I was doing some reading on Kal's site, where he has a 7A fuse protecting the #14 wire feeding his PID which is where I got the idea.

I am not calling Kal out but that doesn't make sense. Running 14 gage wire to the PID is just rediculous. As jkarp pointed out the PID draws milliamps. A 7 amp fuse doesn't make sense for a device that draws milliamps. That PID will be on fire before the 7 amp fuse blows. A fuse should be chosen not only to protect the wire but the device also.

 

[HossTheGreat]

Understood. And I'm sorry if my questions seem trivial. I have a decent understanding of electricity, but the majority of my experience is standard household wiring where you're using the same gauge wire throughout the circuit. Stepping down wiring to devices is new to me and I want to make sure I'm doing things correctly. I'm going to be running out a bit later to pick up some stuff for my build. Where would I be able to find a fuse holder? Radio Shack? Lowes/Home Depot?

 

[kal]

Make's sense. I guess I was thinking more along the lines of protecting the wire from overcurrent, not specifically the PID. I was doing some reading on Kal's site, where he has a 7A fuse protecting the #14 wire feeding his PID which is where I got the idea.

Actually you mis-read (or I did a poor job of explaining). The 7A fuse protects the wiring to all of the 120V devices not just one PID. That includes all the 120V devices including two (relatively speaking) power hungry pumps.

Kal

 

[CaptVideo]

Since I'm only set up for extract brewing right now, I did a modified version of The Electric Brewery. If you have not seen this sight, GO THERE NOW!!! An immense amount of work was put into the site and it contains valuable information for anyone interested in electric brewing.

Thanks Kal!!!!!

 

[HossTheGreat]

Actually you mis-read (or I did a poor job of explaining). The 7A fuse protects the wiring to all of the 120V devices not just one PID. That includes all the 120V devices including two (relatively speaking) power hungry pumps.

Kal

Thanks for the clarification. I understand that now. I guess my initial confusion was after reading the following paragraph of Step 5 of Control Panel (2).

The 7A fuse in the in-line fuse holder is used to protect the smaller 14 gauge wire. Later on we'll be drawing power off the large 10 gauge wire before the fuse to run our power-hungry heating elements.