# Male 110v Receptical?

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#### JAL3

##### Well-Known Member
Has anybody heard of a male 110v receptacle?

I'd like to find a duplex version if possible.

The purpose is to mount on club launch racks in order to connect the "legacy" controller which uses standard 110v extensions. The controler has the female receptacles and and I'd rather not wire up a bunch of m-m pigtails if I can avoid it. I'd like to be able to connect the extension at each end without any adapters.

The closest I have found is pictured below. I also found one I liked better that has a hinged cover plate but it too is a single and, worse, is almost $60. Since I need four per rack that gets pricey quick. #### JAL3 ##### Well-Known Member Thanks for the refference. Much better price. I notice that it says for 125v and I am using regular 110 extension cords. The blades look the same to me but are they? I'm not much of an electrical guy.:blush: #### quickburst ##### Well-Known Member TRF Supporter 110,115,120 .... all the same. I suppose 125 is as well. I'm guessing the 125 is the peak voltage rating. If I measure the outlets in my home, I get about 118-120 volts. I might also add that I'm not an electrician. Thanks for the refference. Much better price. I notice that it says for 125v and I am using regular 110 extension cords. The blades look the same to me but are they? I'm not much of an electrical guy.:blush: #### MarkII ##### Well-Known Member 110,115,120 .... all the same. I suppose 125 is as well. I'm guessing the 125 is the peak voltage rating. If I measure the outlets in my home, I get about 118-120 volts. I might also add that I'm not an electrician. When I stuck a fork in one of mine, that's about how much it felt like, too... :cyclops: MarkII #### JAL3 ##### Well-Known Member I appreciate the info so far. Any chance there's a duplex out there somewhere? #### rokitflite ##### Well-Known Member If I measure the outlets in my home, I get about 118-120 volts. I might also add that I'm not an electrician. Have you ever stayed at a Holiday Inn Express though? #### ben_ullman ##### Well-Known Member The voltage will all be in those ranges. Keep in mind the wire adds ohms per ft so the farther away you get the less voltage/amperage/power etc. Distance is bad for power. Think of your house like a launch setup. The outlets right next to the box are going to have a tad more power than those on the far end of the house due to wire distances and connections. They do exist JAL3 ill look at a couple places for ya that have everything AND the kitchen sink Ben #### SCE to AUX ##### Well-Known Member These things are properly referred to as a "NEMA 5-15 flanged inlet". If you search on that term, you might find a slightly cheaper source. I have never seen a "duplex" version. Use of these types of AC power connectors and extension cords for launch systems is generally a BAD idea, and is a violation of the National Electrical Code. Sooner or later, one of these setups is going to get plugged into 120 VAC power by mistake, and someone hooking up clips at the pad is going to get a nasty shock... #### hardinlw ##### Well-Known Member Voltage rating on the outlet is the maximum allowable, so the 125 rating is OK and is the standard. That particular outlet is rated 15 Amps and has parallel blades. A 20 plug (I've only seen a few of these) will have one of the blades rotated 90 degrees and a 20 Amp outlet will have one normal slot and one T-shaped hole that will take either the 15A plug or the 20A plug. #### quickburst ##### Well-Known Member TRF Supporter When I stuck a fork in one of mine, that's about how much it felt like, too... :cyclops: MarkII That explains a lot. #### jsdemar ##### Well-Known Member Sooner or later, one of these setups is going to get plugged into 120 VAC power by mistake, and someone hooking up clips at the pad is going to get a nasty shock... Extension cords have been used in launch systems for 20+ years and I've never heard of anyone plugging something into an AC outlet. Launch systems are used away from buildings with line power. And if someone is smart enough to launch a rocket, one would expect they'd know better. Back to the question... the panel-mount male AC plugs use a different prong arrangement than a standard power cord. They're expensive and not very practical. The cheapest option is to buy short 3-conductor power cords with only the male connector on one end, and stripped leads on the other. ($1 to $3 each). Or, if it's cheaper, buy a short cord and cut off one end. I've used these on pad boxes, strain-relieved on the box and about a foot dangling outside to plug into an extension cord. Use a standard AC receptacle on the distribution box. Or use the other end of the short cord you cut off. -John #### bobkrech ##### Well-Known Member http://www.McMaster.com Part Number: 8036K1$13.41 Each

Not inexpensive but allows the use of 100' extension cords.

A potentially cheaper solution is to use cheap 4-wire phone or 8-wire data cables to carry low continuity and relay activation currents, and use inexpensive automotive relays at the pad to carry the high igniter currents.

Bob

#### SCE to AUX

##### Well-Known Member
Extension cords have been used in launch systems for 20+ years and I've never heard of anyone plugging something into an AC outlet.
Neither have I. That doesn't change the fact that it is bad engineering practice and an electrical code violation.

Launch systems are used away from buildings with line power.
In most cases. I have been at at least one launch where there was a 120V generator in use to operate the PA system and other stuff.

And if someone is smart enough to launch a rocket, one would expect they'd know better.
If only that were true. Unfortunately, a look at YouTube or other places online will show a lot of "stupid rocket tricks"....

bobkrech said:
A potentially cheaper solution is to use cheap 4-wire phone or 8-wire data cables to carry low continuity and relay activation currents, and use inexpensive automotive relays at the pad to carry the high igniter currents.
Definitely the nicest way to go, especially for long controller to pad distances. Cat5 cable is MUCH cheaper than multiple runs of extension cord...

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#### Ted Cochran

##### Well-Known Member
Be a little careful with long runs of signal cable--the voltage drops can be significant. It really isn't designed to carry 12v DC current sufficient to energize 30 amp relays, so you have to be careful with your selection of switching/relay components, so what you save in cable you may lose in component costs. You may also find that, per foot, you can 100' extension cord for about the same cost, especially if you wait for sales.

#### JoeG

##### Well-Known Member
Use of these types of AC power connectors and extension cords for launch systems is generally a BAD idea, and is a violation of the National Electrical Code. Sooner or later, one of these setups is going to get plugged into 120 VAC power by mistake, and someone hooking up clips at the pad is going to get a nasty shock...
Yes, but you can use copperheads for clusters.

#### Sandy H.

##### Well-Known Member
I was initially surprised by Ted's concern regarding voltage drop in a signal wire (Cat5 or similar) to close a relay. I mean, the point of a relay is to cut the current draw, so a low current closing the relay should be of no concern, even with small gauge wire, right? But instead of instantly posting that it should be fine, I decided to ballpark some numbers to see what the drop really could be.

Assume:

Typical automotive 30 amp relay with a common coil voltage of 75 ohm
24ga Cat 5 wire (25 ohm/1000ft nominal resistance vs. length)
100 ft from control to relay
12 Volt battery near relay
Power supplied to switch from battery near relay, not a separate batter at the switch

Then:

R=75 ohm+ 100ft*(25ohm/1000ft) [from battery to switch] + 100ft*(25ohm/1000ft) [from switch to relay] = 80 ohm equivalent circuit resistance

V=IR -> I=V/R;
I= 12V/80 ohm = .15 Amp closed circuit current

V=IR;
V=.15 Amp * 75 ohm [coil resistance] = 11.25 Volts across the relay coil

So, almost 10% of the supply voltage is lost in the signal wire from the battery to the switch back to the relay. Some relays may not have a problem with this, but once the relay closes and current goes from the battery to the ignitors, the voltage may sag a bit and as the launch day wears on, maybe the battery voltage will go down as well. In the end, maybe that 10% loss would yield an inconsistent latch for the relay. Then again, maybe not, depending on the relay specs.

But, switching to, say an 18 ga. relay trigger lead instead of the 24 ga. would yield only 6.5 ohm/1000ft loss, for a total voltage loss of just under 1/4V, leaving 11.8V across the relay.

Switching to a relay with a higher impedance coil, say 200 ohm instead of 75 ohm, while maintaining the 24ga wire would give you 11.7V at the coil. There are obviously many different combinations.

One remaining factor is that your typical Cat5 type connector is probably not suited to the abuse it is likely to take getting plugged in over and over, packed in a box with 20# of other junk piled high on top of it. Plus, when the connector does inevitably break, how easy is that 24 ga. wire going to be to scab together to continue the launch? Maybe the simple ruggedness of an extension cord or other cord type is worth the bulk/cost penalty.

I guess to me, the bottom line is that if you decide to use a relay system, choose the components to work together. Size the relay/wire to ensure that the proper voltage to close the relay will be there when needed. Choose the connectors to take the level of abuse you think the system will undergo. And finally, when a well respected community member states something that doesn't necessarily mesh with your initial thoughts, go ahead and do some math. You might find out that his experience outweighs your random guess.

Sandy.

#### JAL3

##### Well-Known Member
Wow.

That a lot of response. I appreciate it all.

Let me reiterate that what I want to do is to maintain some backward compatability with our existing equipment. I want to move in the direction of relays but also want the flexibility to be able to use tha pads in a wide variety of locations. That is the genesis of the question.

Originally, I had in mind the female duplex outlets and figured I would rig a series of M-M pigtails to connect the extensions. I might still do that but I like the idea of a more finished look with a direct plug into the box and not having to worry about sticking an adapter into the line.

I had to leave town this morning for a little while and just got back. At that time I had just glanced at the first few replies; most ot the others had not yet been posted. As I drove to Nixon and back, I was convinced in my mind that I would bite the bullet and order the one mentioned above with the cover; I just like the clean looks of it. I would rather not use up so much of the real estate on the back of the box but I was going to do it. Then I began to wonder.

I ahve not seen one of these things first hand. Most of the heavier guage extention cords I have see have a distinct profile, non circular, on the female end. I wonder if it will even fit as I expect it to.

Now I'm back to wondering about making up a bunch of pigtails. I would rather not but, as of this hour, I remain undecided.

#### plano-doug

##### Well-Known Member
Extension cords have been used in launch systems for 20+ years and I've never heard of anyone plugging something into an AC outlet. Launch systems are used away from buildings with line power. And if someone is smart enough to launch a rocket, one would expect they'd know better.
John,

I'm kinda torn on this one. One of our British comrades was making the same complaint as Bob a while back, that using "mains" connectors would eventually result in someone causing an unsafe voltage to be applied. I tend to agree that there aren't any 110 outlets in the pasture in McGregor nor in the Wells brothers' farm in Windom. But, as Bob pointed out, there are generators. And, for that matter, outdoor wiring is becoming more common.

So, even if using extension cords is safe for now, we probably ought to be thinking about long term plans to use some other connector technology. For example, with cat-5 (as cited here-in) being ubiquitous, we can ride its low-cost coat-tails much the same as has been done with the cheap, orange cords. In this case, we'll be doing all relayers, although, most of the orange cords I've ever used were driving relayers anyway, so the different line characteristics shouldn't pose any problems.

I tend to view using the old, orange cords as a cheap and clever way to string up the long runs on the range, but I also see them as being similar to living near a cliff. Having a standing rule of staying away from the edge isn't good enough; the only way to ensure long term safety is to build a fence.

Doug

.

#### jsdemar

##### Well-Known Member
I tend to view using the old, orange cords as a cheap and clever way to string up the long runs on the range, but I also see them as being similar to living near a cliff. Having a standing rule of staying away from the edge isn't good enough; the only way to ensure long term safety is to build a fence.
There are many options for bulk wire and connector styles. But, you can't buy bulk stranded wire anywhere near as low cost as extension cords. Plus, the AC connectors are premolded on at no extra cost, they're heavy-duty and water resistant. I've seen many RJ-11/12 cat-5 type interconnects on launch systems and they are prone to breakage and corrosion. Likewise with plastic molex connectors.

Of course, if money is no object, like the Mil/Aero stuff I've designed, just use Amphenol circular metallic connectors at $100 each. More like a brick wall than a fence. If you're really worried about some bonehead plugging a pad box into a real AC outlet, put some protection circuitry in there. I use the ground prong for 12V distribution, the neutral for the return, and the "hot" side for the relay actuation signal (which doubles as the continuity signal back the controller). That way, there is no path path for 110V AC to the igniter leads if it gets into the hands of Bubba Bonehead. All that needs to be protected is overvoltage on the relay coil which is simple and low-cost to do. -John #### spacecadet ##### Well-Known Member I'd echo not using mains connectors for low-voltage purposes, just for idiot-proofing. The club ought to think about changing over when the current kit needs replacing. There shouldn't be the faintest possibility of mains voltage appearing on the prongs of a male plug or connector. I'm not an electrician, just someone attached to his heart. I've had the odd shock and you don't have to be particularly careless to get one. Over here it's 240V as well. #### SCE to AUX ##### Well-Known Member I've seen many RJ-11/12 cat-5 type interconnects on launch systems and they are prone to breakage and corrosion. That's what these guys are for: A "mil-style" assembly that fits over standard RJ-45 plugs/jacks, to provide protection and strain relief. These are seeing wider application as ethernet networks become commonplace in industrial environments. Sold by Amphenol and one or 2 others. Of course, if money is no object, like the Mil/Aero stuff I've designed, just use Amphenol circular metallic connectors at$100 each. More like a brick wall than a fence.
That's what I did with the controller shown here:

The connectors CAN be found in surplus, but it will take a bit of digging/luck. They certainly take the abuse unlike anything else! The older threaded Mil-C-5015 types are a little bit cheaper, and more available in surplus channels. Check ham radio fleamarkets and industrial surplus dealers.

The "CPC" circular plastic series from AMP is a good "budget" alternative to the full-on milspec stuff. Available in a huge range of configurations:

http://www.mouser.com/catalog/636/1256.pdf

I use the ground prong for 12V distribution, the neutral for the return, and the "hot" side for the relay actuation signal (which doubles as the continuity signal back the controller).
Using the ground prong for a hot conductor limits you to using non-metallic enclosures, because the ground terminal of a standard duplex receptacle is also tied to the mounting strap/screws.

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#### Micromeister

##### Micro Craftman/ClusterNut
TRF Supporter
I have to agree! use of extension cords and AC components is really not a wise decision John.
There are plenty of multi wire connectors that can be used that will remove the potential for misuse.
Just a little time spent reseraching allied electorics and other sites should give you plenty of good alternatives.

I'm a big fan of Amphenol connectors (Allied Electironics) as well as 4 pin Mic connectors and plugs from Radio shack for our launcher/controller use. The numbers in the drawing below are still good and current.

Hope this helps a little.

#### Sandy H.

##### Well-Known Member
What if you bought the electrical cord and then intentionally cut off/pulled out the hot connector on the male end? At that point, even if someone plugged it in, you would only have a neutral and ground connected. While I know for a fact that many systems end up with neutral problems, I assume it would be less hazardous than having the hot connected. Of course, you now only have 2 wires instead of three to work with.

Just a thought.

Sandy.

#### j.a.duke

I'm a big fan of Amphenol connectors (Allied Electironics) as well as 4 pin Mic connectors and plugs from Radio shack for our launcher/controller use.
I've designed my small controller with the following connectors:
Neutrik powerCON

If you need more conductors, their speaker connectors would do the trick.
speakON

Neutrik also has ruggedized RJ45 connectors as well.

There are other brands of similar products as well, but I can't find them in a google search.

The prices aren't too bad-for less than \$100 I ordered several pairs of connectors.

At the moment, the controller is just a design and parts, but I hope to get a bit of work in on it this winter (which I said about this time last year).

Cheers,
Jon

#### jsdemar

##### Well-Known Member
Using the ground prong for a hot conductor limits you to using non-metallic enclosures, because the ground terminal of a standard duplex receptacle is also tied to the mounting strap/screws.
I've never used a standard duplex receptacle for a launch system. Therefore, never had to work around that problem.

There is still no argument that power cords and power connectors are robust and lower cost than any other option. Even the surplus Amphenol mil-type connectors are more expensive from a hamfest, etc. They're also limited to the wire gauge you can solder to them... you can't just cut off the connectors from an AC extension cord and use those connectors. With AC cord pigtails and extensions cords, no soldering or connectorizing is needed. Internal to pad boxes and distribution boxes, crimp-type lugs and fast-ons are best for high-current connections.

I've been using power cords on launch systems since 1972. The 32-pad launch system I designed in 1996 is still in continuous use for many large launches, including all NYPOWERs, 2 NSL's and 2 NARAMs. Many other clubs use similar arrangements with power cords. The clubs I've been affiliated with since moving to New Mexico several years ago also use extension cords and AC connectors. Nobody plugs them into line power because there's no reason to. If they did, it would burn out a relay coil without causing harm or electrical hazard to the idiot who tries it out of dumb curiosity.

Certainly, there is a point on pure principle to insist that AC plugs shouldn't be used. But, the same attitude could apply to banning many other things that are co-located that might be misused. For example, someone could plug an RJ45/Cat5 connector from a launch controller into their laptop port and fry the ethernet interface.

-John

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#### artapplewhite

##### Well-Known Member
I have to agree! use of extension cords and AC components is really not a wise decision John.
The decision to use AC extension cords wasn't John's, it was mine. I built the system he is using more than 5 years ago and with only minor maintenance, it's still working.

BTW: The extension cords we use are bright orange and they still get tripped over and the controller gets knocked to the ground a couple of times each launch but it keeps working because the connectors are rugged.

I did it that way for all the practical reasons given already, namely cost, reliability, ruggedness and availability. I've seen a lot of very high tech launch equipment fail in the middle of a Texas cow pasture just because someone tripped over a nearly invisible CAT 5 cable and broke the connectors or it got how and the microcontroller failed, etc. With the club launch controller is disabled in the middle of the launch folks have to bring out their personal Estes Electron Beam controllers with their skinny 15 foot cord just to keep the launch going.

Yes there is always a remote possibility of hooking something up to a 120 VAC source, but if you're setting up a rocket launching system and you're so "zoned out" you would make such a mistake, then you should consider staying home to begin with.

These things (AC extension cords) aren't made with built-in homing devices to seek out a power outlet at all costs. It takes a human being making a conscious choice. This is what you do at rocket launches at ever step. If you don't have your head IN the game then you're going to get hurt in a dozen other ways and probably hurt someone else in the process.:bangpan:

The choices for many small rocket clubs are either an unreliable launch system, no system or a system that can be build and maintain inexpensively by using what is readily available. After all, the point is to have a safe ROCKET launch not host a NEC convention. In a hobby as unpredictable and risky as rocketry, you can always find many, very good reasons not to do something. That's why there are so few people involved in amateur rocketry as it is and it's so hard to find a place to fly.

BTW: I'm thinking of offering a 4 pad version of the system John is using as a kit if anyone is interested. It uses AC extension cords (not included, it cheaper to buy them at Walmart than to mail them) between the controller and pads, AC Duplex outlets for connectors at the launch controller. Common AC wall switches for pad selection. For wiring at the pad, it uses 3 prong AC plugs, 3 feet of zip cord, banana plugs and slip-on (easily replaceable) alligator clips. It is housed in a plastic tackle box. :jaw:

Art Applewhite
Chief Rocket Scientist

If you build something that is truly fool-proof, then only a fool would use it.

#### jsdemar

##### Well-Known Member
The decision to use AC extension cords wasn't John's, it was mine. I built the system he is using more than 5 years ago and with only minor maintenance, it's still working.
Just to be clear, I'm not the "John" that Art is referring to. But, I do agree 100% with the reasoning in his post.

-John DeMar
Las Cruces, NM
TRA L3