How do i wire a 3 prong timer box to a 4 prong 240 outlet???

[HookedonPonics]

i have a 30 amp timer box and was planning on wiring it into an unused 30 amp 240 dryer outlet but the timer box has a 3 prong plug and the outlet is 4 prongs, is there anyway i can SAFELY connect them -Dee

 

[up yours]

Had same problem if you look in forums under the electricity section I would post you link but I am not good w/ computers and I do not wish to burn down your home I will let a more qualified person finsh helping you and I would not post your name again ok anonymus is best thanx

 

[InvisibleM]

What is your timer going to power? 240 power is two hots a neutral and a ground, the neutral may not be needed. Your timer box would have two hots and a ground (3 prong plug), which means you only have 240 volts and don't need to hook up the neutral.

So get rid of the timer cord, run a 10-2 romex with ground from the outlet to the timer....

And you may want to turn off the breaker.

 

[Nobodynobody]

If the dryer box has punch out holes. Kill the breaker to that socket. MAKE SURE ITS DEAD, open the box up and unscrew the dry plug from the wire. Take a screw driver & hammer and punch out a side hole on the box(you can buy a plug or re sizer if there is a hole you don't like) Get some flux and re pull the wire to where you are needing the power. Keep color code and any wire you don't use. Place a wire nut on it to keep anything from making contact. Take photos and measurements to your hardware shop to get any kind of connectors or fittings that might be needed to safely run the wires. If you get asked what your doing. Say your moving the service room few feet down and the new dryer cord is different. They wont know if your a renter. WHO CARES.

Fine words. Never pull over 75% load

 

[BudGood]

i have a 30 amp timer box and was planning on wiring it into an unused 30 amp 240 dryer outlet but the timer box has a 3 prong plug and the outlet is 4 prongs, is there anyway i can SAFELY connect them -Dee

Yes, just get a different cord, one that will fit the plug, and rewire your timer box, leaving the neutral (white wire) in the new cord unused and capped off. You can find the cords in the electrical section of the hardware or home improvement store. Keep your old cord in case you ever need to switch it back.

You'll be connecting two hots (probably black and red) and a ground (green), the white in the cord is un-needed (it's used in some appliances to create a 120v power source for clocks, and other things inside the appliance). It'll either be a range cord or a dryer cord.

Oh yeah, you can pull up to 80% load safely on any circuit. For example, on a 15A circuit, 12, on a 20A, 16, on a 30A, 24.

Sometimes I read some of the advice given on these forums, and I wonder if the original post was even really read or comprehended. But I digress...

Hope that helps! :rasta:

 

[HookedonPonics]

so if i just plug the timer box into a 240 volt 3 prong outlet and connect it with a 10/3 cable to a 4 prong plug that is connected to the dryer outlet and cap the neutral on the 3 prong end, will it work and will it run safely with no chance of an electrical fire?

 

[Nobodynobody]

so if i just plug the timer box into a 240 volt 3 prong outlet and connect it with a 10/3 cable to a 4 prong plug that is connected to the dryer outlet and cap the neutral on the 3 prong end, will it work and will it run safely with no chance of an electrical fire?

you got it. I have seen some high power relays that say cap the neutral off. On one of my 240v plugs. I Tied the Ground&neutral, Then use a short pc. of cord to do what we call a PIG TAIL for the 3ed spot. If you do the pig tail make sure the wire nut is meant for that size and that many wires.

Your almost there. GL

 

[dmtcorey]

Yes, just get a different cord, one that will fit the plug, and rewire your timer box, leaving the neutral (white wire) in the new cord unused and capped off. You can find the cords in the electrical section of the hardware or home improvement store. Keep your old cord in case you ever need to switch it back.

You'll be connecting two hots (probably black and red) and a ground (green), the white in the cord is un-needed (it's used in some appliances to create a 120v power source for clocks, and other things inside the appliance). It'll either be a range cord or a dryer cord.

Oh yeah, you can pull up to 80% load safely on any circuit. For example, on a 15A circuit, 12, on a 20A, 16, on a 30A, 24.

Sometimes I read some of the advice given on these forums, and I wonder if the original post was even really read or comprehended. But I digress...

Hope that helps! :rasta:

I know this thread is 5 years old but I have already wasted a haft day of reading and still can't figer this out ..I have my timer box that has the 4 prong cord which I cut and want to hook up to my 3 prong male adapter .I get just capping off the natural but my timer box has 4x 120v outlets as well so I'm left wondering how to hook my box up with these extra 120 v outlets ..?
Do I connect the nutiral with the ground in the male adapter ?

 

[Seed Buyer]

Its simple, if you only need 240 power to run the ballast then you can wire the hot, hot and ground from the timer to your 3 prong male piece and plug into the dryer outlet. If you want to use the timer as manufactured ( 240 volt for the ballast and 120 volt for other equipment) you will have to run all 4 wires. This will not work with an old school 3 outlet dryer receptacle. If the later is the case, I would just go to Lowes and buy some new 10/3 Romex and run it from the grow room to your breaker box. You can run it through the attic, you can run it in the crawlspace under your house. Then tie it right into a 30 amp double pole breaker. Any body who is going to be a serious grower needs a multi meter and understanding of the homes electrical system. A cheap $20 book on electrical work would be a good buy. Its easy to grasp once you have a book with some pictures.

 

[dmtcorey]

Its simple, if you only need 240 power to run the ballast then you can wire the hot, hot and ground from the timer to your 3 prong male piece and plug into the dryer outlet. If you want to use the timer as manufactured ( 240 volt for the ballast and 120 volt for other equipment) you will have to run all 4 wires. This will not work with an old school 3 outlet dryer receptacle. If the later is the case, I would just go to Lowes and buy some new 10/3 Romex and run it from the grow room to your breaker box. You can run it through the attic, you can run it in the crawlspace under your house. Then tie it right into a 30 amp double pole breaker. Any body who is going to be a serious grower needs a multi meter and understanding of the homes electrical system. A cheap $20 book on electrical work would be a good buy. Its easy to grasp once you have a book with some pictures.

Thank you for the reply .

That's a great idea to just wire into the exiting 10.3 already running to the outlet ,I'll just uninstaul the outlet and splice in my 10.3 running from my timer board , should already have plenty of length so I should be fine .

Once again thanks for pointing that out !

 

[We Solidarity]

I've bought the 240v replacement dryer plugs at home depot and just wired that to the timer with romex, that way I can still use the dryer if I want and just switch out the plug. (helps to be able to clean clothes in a grow house - I used to just throw mine in the dryer for 20 or 30 minutes...kills bugs and helps with the fresh herb smell)

 

[Seed Buyer]

I thought your dryer was a female 3 receptacle outlet? Does the female dryer receptacle have 3 or 4 holes. If the dyer receptacle has 3 holes then it it is only wired for 240 power and you will not be able to wire in your timer box and still use the 120 volt outlets on the timer box.

10/3 wire actually has 4 conductors (2 hot, 1 ground, 1 neutral)
10/2 wire actually has 3 conductors ( 2 hot & 1 ground)

 

[hiboy]

The correct terminology is
120/240v 4 prong
240v 3 prong
Both have two hots and a ground. The 120 refers to an additional wire.... the neutral
Hb