Any recommendations on a good source for some wire?

Perhaps you could tell us where you are located ?

 

I'm in Northern California in the coastal range, elevation 1200ft and very rural. Lightning is rare. Pressure switch idea is not ideal for my circumstance because I'm pumping almost 600ft vertical and already at really high pressure, plus tuning it to shut off exactly when the tank is full would be difficult.

As to wire I'm looking for anything that is functional for this purpose and hopefully semi-economical. Any recommendations on twisted vs straight, and shielded vs unshielded..? It will have protectors on both ends and be in dry conduit 3ft underground.

 

Hard to beat cat5 or cat6 cable.

Just look for a good price.

You will have some extra pairs and it's easy to find locally if you ever have to re-pull a section.

They make a 22awg version if you can find it.

Use each pair for a conductor and have a pair left to ground on one end.

 

http://www.allelectronics.com/make-a-store/category/825800/wire/cable/telephone/data/1.html

All Electronics in Van Nuys sells cable in bulk quantities.
I don't think there is any need for the wire to be shielded, like inwo said Cat5 is probably your best bet.

 

Ok from this post and another I've had recommendations to just stick with a regular 24 volt relay. I was thinking that was the whole reason of the SSR being recommended was that anything else would require bigger wire. Call me a bonehead I thought I read somewhere that even with DC, a run/circuit that long could cause stray bleed through voltage issues between the two wires..?Any recommendations for a normal 24 volt mechanical relay that will operate effectively with a 4300 ft 22 gauge wire switch circuit..? There is such a plethora of relays and crunching the numbers is kind of out of my field of expertise! Just considering my other options besides the SSR route..? Thanks for everyone's input.

 

I don't know what you mean by voltage bleed through issues. The normal wire insulation resistance is so high that any leakage would be negligible, even for such a long run (as long as the wire stays dry).

22 gauge wire has a resistance of about 16.14 ohms per thousand feet so the 4300 ft. (round trip) would have a total resistance of 69.4 ohms. If you double two of the wires each way, the resistance would be reduced by half to 34.7 ohms. That will readily power a small mechanical or solid-state relay. This small relay would then control the larger pump relay.

Here is a general listing of 24VDC relays. This is a typical example that should work for you. It requires just 15mA to operate so the voltage drop in a single line would be only 15mA * 69.4Ω = 1.04V, which will cause no problems.

 

Ok from this post and another I've had recommendations to just stick with a regular 24 volt relay. I was thinking that was the whole reason of the SSR being recommended was that anything else would require bigger wire. Call me a bonehead I thought I read somewhere that even with DC, a run/circuit that long could cause stray bleed through voltage issues between the two wires..?Any recommendations for a normal 24 volt mechanical relay that will operate effectively with a 4300 ft 22 gauge wire switch circuit..? There is such a plethora of relays and crunching the numbers is kind of out of my field of expertise! Just considering my other options besides the SSR route..? Thanks for everyone's input.

Many of my suggestions, such as post-14 used relays, and line resistance of 80 ohms.(guess)
Less line resistance means 24vdc relays and no compensation rheostat needed.
The tyco-xt coil (post 13) is 1400 ohms. in 24v version.

Do you dismiss them out of hand, or need more explanation?

I do believe you need some sort of line failure alarm or protection, unless overflow is no problem.

 

I am not into long wires, but isn't voltage drop the basis for 4 to 20 mA control systems? 20 mA through 100 Ω is still just 2V.

John

BTW, Is this a vineyard?

 

I am not into long wires, but isn't voltage drop the basis for 4 to 20 mA control systems? 20 mA through 100 Ω is still just 2V.
...................

Yes, a 4 to 20mA control loop is used to avoid the errors cause by wire resistance. The loop is also relatively noise immune. But that's used for proportional control systems. This is just a simple bang-bang (on/off) control loop.

 

First off thanks for all the input. I don’t dismiss anything out of hand, just gathering ideas. It’s like Crutschow says: This is just a simple bang-bang (on/off) control loop! Nothing more I want to keep it as economical, functional and simple as absolutely possible. Just trying to determine which route is best to go with (advantages/disadvantages) a normal 24 volt mechanical relay or an SSR…?

About RF interference…. Just how close to the radio station would one have to be to develop 1.8volts DC at 4ma on the wire to the tank and back..? I can’t see it being a serious issue for me. I’m in the boonies, but I'd still be interested in knowing.

Overflow protection for this circuit is not an issue I am worried about. I’ve pumped out the overflow tank drain for years with the mechanical timer set-up. If it fails on I will catch it with a visual inspection.

Sorry if I’ve come across as a bit slow I just haven’t mathematically analyzed circuits in so long that it’s made me lazy. I’m kind of like electricity I take the path of least resistance which was through this forum post.

I came across this Signal Control cable/wire 20 AWG (10 x 30) Annealed Stranded Tinned Copper Wire, 2 Conductor Unshielded Multi-Conductor 300 Volt Consolidated Cable UL Style CM/CMG. And can pick up 2150 ft for around $200.00. Any reasons not to use this..? Keep in mind this is a personal homemade non commercial application. 4 conductor cable is not that much more expensive ether and gives me some back-up wires. It is close in price to Cat5 22awg wire.

While I’m at it any help with picking a 220vac to 24vdc power supply to run the relays discussed in this post would be appreciated. I don’t know where to start in choosing one.

Much thanks for the help

 

....................
About RF interference…. Just how close to the radio station would one have to be to develop 1.8volts DC at 4ma on the wire to the tank and back..? I can’t see it being a serious issue for me. I’m in the boonies, but I'd still be interested in knowing.

You'd likely have to be fairly close. Parallel wires in a cable tend to suppress any voltage from RF pickup because the polarity of the pickup in the two wires oppose each other in the closed loop and thus cancel each other. In other words it generates a common-mode signal which is ignored by the relay and generates little differential voltage which would operate the relay.

I came across this Signal Control cable/wire 20 AWG (10 x 30) Annealed Stranded Tinned Copper Wire, 2 Conductor Unshielded Multi-Conductor 300 Volt Consolidated Cable UL Style CM/CMG. And can pick up 2150 ft for around $200.00. Any reasons not to use this..? Keep in mind this is a personal homemade non commercial application. 4 conductor cable is not that much more expensive ether and gives me some back-up wires. It is close in price to Cat5 22awg wire.

That wire should work also, but I would definitely get the 4 conductor cable for a redundant backup. I would get that or Cat5, whichever is cheaper.

But I am curious. How are you going to string this through a couple thousand feet of conduit?

While I’m at it any help with picking a 220vac to 24vdc power supply to run the relays discussed in this post would be appreciated. I don’t know where to start in choosing one.

Just about any commercial 220VAC to 24VDC power supply should work. It could be a small wall-wort type supply such as one of these since it only has to supply less than a tenth of an amp to operate the relay.

 

+1

Cat5 , just a good choice for lots of reasons.

"just a simple bang-bang (on/off) control loop!"

Yet, with just one more relay, a shorted cable or protector, would not keep pump running.

 

Any reason why 24Vac plus 24Vac relay should not be used? All contacts would last much longer and you don't have delayed action when de-energized (due to possible line capacitance on the long run). Only needs a small transformer with nominal 24V AC output as a control power source.

 

Ac should be fine. IMO

I'm going to take another shot at using both NO and NC float switch contacts.

Just because!

 

Hello again

I’ve been tied up with other things with work and off this for a while now but I just wanted to say thanks to everyone for all your input on my project. I have everything but a few misc items rounded up now to do this project. I like the circuit diagrams I’m just trying to go a little simpler route/ON OFF loop. I bought 4 conductor 22awg wire, full length/continuous piece roll. Two conductors for the circuit & 2 for future back-up/insurance.

My last items are fuse protection & surge protectors. To be honest I don’t know diddly squat about Telcom and Movs protectors! What’s better Movs or Telco, proper sizing and help on how and where to incorporate those would be helpful. Again trying to go the simplest route possible here. Is it the same set-up on both ends..? Line to line and line to ground..?

What would be a recommended fuse rating for the 24vdc loop protection with my components?

Thanks again

Here are my system components below minus protectors and fuses:


SSR Relay: OPTO 22 240D3 DC Control SSR, 240 VAC, 3 A
http://www.coleparmer.com/Product/O...474-43?referred_id=5576&ProductID=EW-68474-43


Normally closed model (low level) Narrow angle mercury activated float control switch normally open.


Power Supply: 7.5 to 240 Watt, Single Phase, UL508!
Idec PS5R Standard Series

http://www.wolfautomation.com/produ...ingle-phase-ul508br-idec-ps5r-standard-series


Power Relay: Enclosed Power Relay, 25A, 200/240VAC, DPST
http://www.grainger.com/product/OMR...m/rp/s/is/image/Grainger/2XC19_AS01?$smthumb$


Wire for run: Part# 5406-CL, 22 AWG (7 x 30) 4 Conductor Unshielded 300 Volt UL Style CM/CMG Multi-Conductor Consolidated Cable
http://products.conwire.com/item/ca...e-ul-cm-cmg-ul-style-2464-csa-ft4-cmg/5406-cl

 

Ac should be fine. IMO

I'm going to take another shot at using both NO and NC float switch contacts.

Just because!

Hello INWO
I just got back to my project again. Thanks for your circuit diagrams. Any chance of getting one going the simpler route NO (without protection) incorporating my system components I've put together. Just posted them. Like I say there I don't know diddly squat about Telco & Movs! Much thanks and appreciation for the input and help.

 

Phone,& earlier,Telegraph, companies have operated relays over cable runs of tens of miles & greater for over a hundred years,so I doubt if you will have any major problems.
From what I remember,the coils on these "Post Office"relays is around 1200 Ohms,so if you get something similar,you should be good to go!
The only time I've seen major problems with relays due to lightning was with "reed relays"----the contacts used to weld together in the "made" position.

 

I've had good luck with these guys:

http://mycablemart.com/

 

SSR Relay leaks voltage/51v...? Hey folks back on my project after a long absence for lack of time to get to it again after getting the wire finally pulled through my conduit. Anyway quick question..? from the parts mentioned above I threw together a quick mock-up of my controller on a piece of wood and hooked it up to see if it would work..? And it does... kind of. My float switch has 24vdc running through it and it triggers/switches my 3-32vdc activated OPTO 22 240 on (one leg) of power going to my 240vac relay and turns the pump on......... but when the float switch moves to the up position/tank is full and circuit goes to the open position the leg of power going through the SSR to the relay still indicates 51 volts ac and the relay continuously hums or chatters. Actually it indicates 51 volts before that but it does not chatter until it's been activated and trying to shut off. I bought a spare SSR and it does the same thing! Am I missing something obvious here? The SSR just has one leg of the 240VAC going through it to my relay. The other leg just goes straight to the other side of the relay coil. Any help appreciated. Thanks

 

Sounds like either the SSR has leakage or there is a snubber capacitor across the SSR output that is carrying the stray voltage.
You might try adding a resistor or a small light bulb (such as a night light) in parallel with the relay coil to bypass some of the leakage.