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IcutMetl
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# Posted: 30 Jan 2024 04:24pm - Edited by: IcutMetl
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I’m looking at a generator with a TT-30R outlet (120v, 30a). The generator inlet boxes I’ve seen utilize a L14-30P connection (120/240v, 30a). The adapters I’m seeing from TT-30P to L14-30R tie the two hits together to energize both hots with 120v. I’m drawing a blank how to wire the L14-30P generator inlet box into a 120v sub panel. Could someone fill in the blanks?
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Brettny
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# Posted: 30 Jan 2024 08:07pm
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Why do you need a generator inlet box? Is this on grid?
From what I gather the goal is to supply a 120v pannel on both sides of the panel? If that's what your trying to do just make the junction in the panel. It's easy for anyone coming after you to see what's been done. For the generator connection side you can simply use a outdoor rated extension cord with the proper end cut off in the pannel or junction box.
If this is a on grid system use a proper system with interlock.
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IcutMetl
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# Posted: 30 Jan 2024 08:32pm
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It’s an off grid cabin- no interlock switch needed. As mentioned, the info I’m asking for is how to wire from the generator inlet box into an electrical panel.
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toyota_mdt_tech
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# Posted: 30 Jan 2024 08:50pm
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Wire it normally and just put a jumper across inside the panel to tie both legs together, size wire properly.
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gcrank1
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# Posted: 30 Jan 2024 09:15pm - Edited by: gcrank1
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Are you using something like a RV inlet; ie, an inset male connecter that you plug the gen cord into?
(don't ever use two male ends on an extension cord!)
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Brettny
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# Posted: 31 Jan 2024 05:33am
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The hot wire you would split and run to both buss bars.Quoting: IcutMetl . As mentioned, the info I’m asking for is how to wire from the generator inlet box into an electrical panel
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IcutMetl
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# Posted: 31 Jan 2024 06:35am - Edited by: IcutMetl
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Quoting: toyota_mdt_tech Wire it normally and just put a jumper across inside the panel to tie both legs together, size wire properly.
Quoting: Brettny The hot wire you would split and run to both buss bars.
Thanks- I understand that. However, as mentioned in my original post about using the TT-30P (coming out of a generator like the Harbor Freight 5000 and many others) to L14-30R (as is common on many generator inlets) adapter, the two hots are bridged. The L14-30 connection is suitable for both 120/240V so it has two hot legs. The adapter ties them both together since the TT-30 connection is only good for 120V; is this making sense? Would I run one leg down each bus in that case?
Google TT-30P to L14-30R adapter for an example. I tried to paste a link but this forum doesn't seem to like that and the hyperlink wouldn't appear.
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IcutMetl
Member
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# Posted: 31 Jan 2024 06:41am - Edited by: IcutMetl
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Try clicking on this URL for an example
URL
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toyota_mdt_tech
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# Posted: 31 Jan 2024 07:53am
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Quoting: IcutMetl The adapter ties them both together since the TT-30 connection is only good for 120V; is this making sense?
Yes, but we are doing the same thing at the panel by jumping both buss bars together. In the end, I suppose it doesnt matter which way you to it. In your case, inside the 240V twistlock coming from the 30A 120, I am certain the hot leg (brass screw) hooks to both the hot lugs inside the plug too.
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IcutMetl
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# Posted: 31 Jan 2024 08:35am
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Quoting: toyota_mdt_tech Yes, but we are doing the same thing at the panel by jumping both buss bars together. In the end, I suppose it doesnt matter which way you to it. In your case, inside the 240V twistlock coming from the 30A 120, I am certain the hot leg (brass screw) hooks to both the hot lugs inside the plug too.
Yes, that’s what I’ve been trying to say about the hots being tied together in the plug/adapter.
I think we’ve driven around in a circle but I got my answer, more or less.
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toyota_mdt_tech
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# Posted: 31 Jan 2024 04:05pm - Edited by: toyota_mdt_tech
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Quoting: IcutMetl I think we’ve driven around in a circle but I got my answer, more or less.
And you got the other option at the panel too which is much easier to do really.
I did that ay my cabin, ran inlet via a 115VAC porch outlet, 12AWG wire, fed panel via a 20A breaker. But only half of it, so I bridged it across the top to tie boith buss bars together.
I just got power in, tie it into cabin in spring, I am on the grid now, so no more feeding via generator. I will still bring my little Honda EU gennies.
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Brettny
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# Posted: 31 Jan 2024 06:33pm
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Its prob better to do in the pannel as you dont need 4 conductor wire..you will if you do it outside of the pannel.
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gcrank1
Member
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# Posted: 31 Jan 2024 07:41pm
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Can't you just run the 220 into the box then split the hot legs to each side for 120 each?
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Brettny
Member
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# Posted: 1 Feb 2024 05:37am
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They have a 120v generator. I believe there trying to use the whole pannel with a 120v system.
Either way 240v is made by useing two 120v legs. If you want 120v off that you would use one of the 120v legs and neutral/ground.
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IcutMetl
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# Posted: 1 Feb 2024 06:08am
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Quoting: gcrank1 Can't you just run the 220 into the box then split the hot legs to each side for 120 each?
That’s precisely what I’m asking; if I can run each of the bridged legs into the panel…one on each side.
I haven’t bought a generator yet; just looking at different options and wrapping my head around that particular wiring scenario.
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gcrank1
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# Posted: 1 Feb 2024 07:43am - Edited by: gcrank1
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Note: Im not anywhere close to an electrician!
And think I misread/misinterpreted your 1st post.
So....
Looking at your original post you say you are 'looking at a gen' with a TT-30R 120v/30a outlet, not a 220/240. It will only have a 3-prong receptacle with one hot, a neutral and a ground wire.
If you run a cord from that to the inlet that has the 4-prong (the other one you mention) and use a 3 prong from the cord adapter to 4-prong on the inlet it is still 120v, just one prong of the 4 isn't used.
You would wire that 120 from the inlet receptacle to the service box (which you have?).
You can bridge the box to use both legs at 120 just keep in mind your total loads from both have to be within the 30a peak (actually some less for steady).
And the wire gauge from the inlet box, as well as the receptacle, need to be 30amp to the box.
IF Ive got this right......
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toyota_mdt_tech
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# Posted: 1 Feb 2024 08:03am
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Quoting: IcutMetl That’s precisely what I’m asking; if I can run each of the bridged legs into the panel…one on each side.
If you have actual 240VAC, hook it up normally. But a generator doesnt really have a neutral like in a "Y/WYE" wound stator, you only have 2 poles, your generator produced half.
Dont bridge it if you use 220VAC. But when its set up like that, then you always have to use a 220V gennie .
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gcrank1
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# Posted: 1 Feb 2024 08:57am - Edited by: gcrank1
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Do you have an inlet box or trying to figure out what to get?
How about a cord from the proposed gen to inlet?
For me, I have a HD RV 50' cord (expensive) so I have to match the end plugs up with what Im using it on.
Decide what you think will work and search it out on Amazon to make sure its available and affordable.
Fwiw, they have the TT-30R inlet boxes, no confusion on how to wire up.
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