Question about power supply wires...

[kamel]

Hey all...quick PSU question for you folks:

I have a Thermaltake Toughpower 1000W PSU, and it has 2 4 pin CPU power connectors, and an 8 pin power connector (in addition to the 24 pin ATX connection). At present time, I only need the ATX 24 pin and 1 of the CPU 4 pin connector. For the sake of cable management, I want to remove the other connectors I don't need. Here are my questions:

Is it OK to cut the extra wires? I plan on saving everything, and if I need them in the future, I will solder the connections back together.

The 4 pin I want to cut is 2 yellow, and 2 black. The 8 pin is 4 black, 3 yellow, and 1 yellow with an orange stripe. Does it matter if when I later solder the wires whether or not I solder the exact same yellow or black that I cut, or can I go black to black, yellow to yellow, and yellow/orange to yellow/orange?

Thanks in advance for your responses!

 

[PurdueRy]

Cutting the wires will increase the likelyhood of a short dramatically. In addition, soldering them back together is not the best connection(solder has resistance) and adds an additional failure point.

I would NOT cut the extra wires. Either bundle them at the top of the case or run some behind the motherboard tray/hard drive cages.

 

[kamel]

What I had in mind was cutting the wires, then wrapping each individual wire in electrical tape. I would then bundle the wires together, and wrap that in electrical tape. Would this still carry the likelihood of shorting out? If each wire is separated and taped, the chances of a short are almost nil, correct? Thanks.

 

[PurdueRy]

Originally posted by: kamel
What I had in mind was cutting the wires, then wrapping each individual wire in electrical tape. I would then bundle the wires together, and wrap that in electrical tape. Would this still carry the likelihood of shorting out? If each wire is separated and taped, the chances of a short are almost nil, correct? Thanks.

Technically...yes. But tape can loosen/fall off(especially electrical tape).

This also ruins your resale value and if you choose to solder the wires back on it could hurt the voltage output on those wires a bit.

 

[kamel]

OK...thanks for your quick responses. I'm running out of room in my case, but I'll try leaving the wires until I absolutely have nowhere to go with them.

Also...if I do decide to cut them, does it matter which black goes back to which black, or which yellow goes to which yellow? Thanks again!

 

[PurdueRy]

Originally posted by: kamel
OK...thanks for your quick responses. I'm running out of room in my case, but I'll try leaving the wires until I absolutely have nowhere to go with them.

Also...if I do decide to cut them, does it matter which black goes back to which black, or which yellow goes to which yellow? Thanks again!

While it shouldn't matter as they should all be a common ground...I would try to keep them together.

 

[NXIL]

I would NOT cut the extra wires. Either bundle them at the top of the case or run some behind the motherboard tray/hard drive cages.

What's that expression?

Cut the wires, light the fires?

That sounds like a really bad idea to me....and a potential Darwin Award entry. (See below)

Thinking outside the proverbial box: get a bigger case? Better airflow/cooling anyway....with a one kilowatt power supply, your machine is cranking out some heat.

Oh, and more more thing--you know in the movie the guy is always trying to figure out which wire to cut as the dramatic music swells in the background? Well, only in the movies does the guy cut the right one.

GL!

NX

http://www.juiceguy.com/Darwin-Awards.shtml

Do It Yourself, Do Yourself In
2000 Darwin Award Winner
Confirmed True by Darwin

(2000, Colorado) Summer is the most blissful of seasons, when our favorite summertime activity -- do it yourself stupidity -- kicks into high gear. Meet Charles, 34, a Denver masonry contractor who created brick and mortar edifices. Charles was in construction. He had worked on houses, he had watched electricians install wiring. He believed this qualified him as a member of the Junior Electrician Society. He figured he could handle any electrical issue that came up around his own home.

One day on the job, Charles was apparently bonked in the head by his bricks. He had the great idea! He would build an electric fence in his own backyard. "An electric fence will keep the dogs in." Charles connected a wire to an extension cord, and managed to encircle his backyard with a 120-V strand of wire without mishap. His dogs will not be sued for puppy support with this security system in place!

The household became accustomed to the fence, and things settled down to normal, until Charles picked up a passion for gardening. Charles had a real nice set of tomatoes, and I'm not referring to his wife. One day he reached for a tomato, put his hand on the electrified wire, and there's really no need to explain what happened next.

Why did this man die? Like other inexperienced people, he thought he knew what he was doing. But his design had two major flaws. Fences constructed for dogs use one-tenth the voltage of cattle fences (which do use 120 volts.) And he needed to install a repeater, which transmits 150-microsecond pulses, to hit a cow with a jolt of juice that cuts off in time to avoid creating a pile of rare steaks by the fence.

The moral of this story is, as always, one of the guiding principles of common sense: if you don't know how to do something, don't do it!

 

[bigi]

Cut them, each @ different length. This will make easier to work on those in the future as well as different lenth cables will less likely contact eachother.
Use heatshrink tubes afterwards to make sure those will not short...
You'll be fine.

 

[kamel]

NXIL...personally, I don't think the situation you describe applies to what I'm thinking about doing, but I guess that's a matter of opinion. If the wires are terminated properly, they are no more dangerous than leaving the power cables hooked up, and having the wires tucked away.

On a side note:
This kind of response is one of the reasons I usually stay away from anandtech...too many people around who just look to give smart ass answers. I had a nice back and forth with PurdueRy, and everything is fine...then someone has to come in and start making comparisons to setting up an electric fence in my backyard? The comparison to cutting bomb wires in a movie...how is that similar at all?


Bigi and PurdueRy...thanks very much for your comments...you were both helpful.

 

[NXIL]

Dear Kamel,

I apologize that my reply was received in the spirit in which it was intended; however, it is truly my opinion that your cutting the wires on your one kilowatt power supply is not a very good idea.

Here is why:

http://en.wikipedia.org/wiki/Capacitor

A capacitor is an electrical device that can store energy in the electric field between a pair of closely spaced conductors (called "plates"). The process of storing energy in the capacitor is known as "charging", and involves electric charges of equal magnitude, but opposite polarity, building up on each plate.

Capacitors are often used in electrical circuits as energy-storage devices. They can also be used to differentiate between high-frequency and low-frequency signals; this makes them useful in electronic filters.
[/b]
Capacitors may retain a charge long after power is removed from a circuit; this charge can cause shocks (sometimes fatal) or damage to connected equipment. For example, even a seemingly innocuous device such as a disposable camera flash unit powered by a 1.5 volt AA battery contains a capacitor which may be charged to over 300 volts. This is easily capable of delivering an extremely painful, and possibly lethal shock.

Even when unplugged, a power supply still packs a huge charge in its capacitors. If you cut through the wrong cable and short out a big capacitor, you might experience enough volts and amps to make your day unpleasant, or, to end it.

And, that is just the start of the problems....cut wires void your warranty, add another corrosion/failure point, or, if they spark, they can start a fire. That would suck.

As for the reference to the wire cutting drama seen quite often in movies, you wrote:

The 4 pin I want to cut is 2 yellow, and 2 black. The 8 pin is 4 black, 3 yellow, and 1 yellow with an orange stripe. Does it matter if when I later solder the wires whether or not I solder the exact same yellow or black that I cut, or can I go black to black, yellow to yellow, and yellow/orange to yellow/orange?

It just sounded really familiar to me:

http://tvtropes.org/pmwiki/pmwiki.php/Main/WireDilemma

http://www.intuitor.com/moviephysics/abyss.html

http://www.schneier.com/blog/a...7/movieplotthreat.html

Note: in Goldfinger, Bond does not cut the wire...an expert walks in just in time does it for him. I think the scene in the movie "Cats and Dogs" is even better: dog has to cut the red wire, and, of course, dogs see in black and white.

I agree with you, perhaps an anonymous forum is not the best place to ask for advice on this subject. Any idea what anyone's qualifications are to answer the question?

These guys are non profit, unbiased, don't sell power supplies, and literally wrote the book on electrical safety. They will answer your question for free.:

http://www.ul.com/about/

Underwriters Laboratories Inc.
333 Pfingsten Road
Northbrook, IL 60062-2096 USA
Phone: +1-847-272-8800
Fax: +1-847-272-8129

Customer Service

UL Customer Service Professionals are available from 7:00 AM - 7:00 PM (CST) at
Phone: +1-877-ULHELPS (854-3577)

E-mail: Submit a detailed inquiry.

http://www.ul.com/

Also, if you don't like modular cables, PC Power and Cooling will customize a wiring harness for you:

http://www.pcpower.com/products/power_supplies/options/

Also, you can contact one of their engineers to ask your question

http://www.pcpower.com/contact/

and I am 99% sure they will reply, and, I am 100% sure what they will say.