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Discussion Starter #1
I'm looking at new air conditioners and they all seem to be 15 amp. Current wall unit is 30 amp, and has a 6-30 receptacle on a 30 amp circuit. My circuit panel is an old Federal Pacific, and while I am planning on replacing it that is still a little ways out. I'm not comfortable swapping breakers on this as I don't trust it...plus the breakers are expensive. Air conditioner is about to die so I'd like some sort of interim solution.

Do adapter cables exist that are fused at 15 amps so it can be used on the larger 30 amp circuit? Any other work around that is safe? I found plenty of adapter cables but none appear to have any sort of a fuse or other overcurrent device in there. Is there anything inherently unsafe about using a cable rated to 30 amps, but limited at 15 amps in order to connect a 15 amp device?
 

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flipping slumlord
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If you change the receptacle to a standard 120V 15/20A 3 prong...
you can do so using the #10 wire in the box now.
But! you need to do the same with any other 30A outlets on the same circuit and you need to change the breaker as well (to a 1P20A).
 

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Discussion Starter #3
I'm aware that I can swap the breaker (and that's the best solution) however given my old and busted panel I'm not sure I want to do that. I'm concerned that the breakers are not attached very well, and removing the cover will allow them to shift or fall off the bus entirely.

Also, I'm not super keen on having to work on a live panel, since there's no main disconnect.
 

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If you can access the wires to the crt. You can install a small sub pnl. And main breaker it 30 A and put in a 15 A breaker to the plugs .all plugs in the crt. Will need to be updated down to 15 A.

Much easier to change breaker, but make sure that it is a dedicated circuit that only powers the plug to the ac.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 

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Discussion Starter #5
It's a dedicated circuit, and it's actually run via conduit out from behind the panel (on an exterior wall) and over to the A/C, which is maybe a 5 foot run.

Maybe I'll look into installing an outdoor rated panel along that conduit run...a bit of work but I'm probably at least 6 months out on getting the main panel replaced and I'd like A/C in the meantime.
 

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I’d be worried that the 15 amp/120V AC isn’t going to do the job. You have 4 times the wattage with 30 amp/240v

While a new AC might be more efficient per watt than your old one, it’s not going to make up for a 4 fold difference.

You need to find the btu rating of your old AC and get something comparable, if you want the same amount of cooling.

If you are shopping the big boxes, they probably don’t carry anything that size.
 

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Discussion Starter #7
This unit looks like it was made in the 80's...its probably older than I am. I don't know the BTU rating, but its only cooling a large room and 10 - 14,000 BTUs should be plenty for it... I also think it's just ancient and not terribly efficient, as it doesn't offer much more cooling than my smaller 120v unit in my bedroom.
 

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Discussion Starter #8
I just looked, and a 25k btu unit is still only a 20 amp circuit... I'm still in the same conundrum. There's also no way the current unit is that powerful. Probably because it's old and dirty, but that much cooling is not necessary for this area.
 

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I'm aware that I can swap the breaker (and that's the best solution) however given my old and busted panel I'm not sure I want to do that. I'm concerned that the breakers are not attached very well, and removing the cover will allow them to shift or fall off the bus entirely.
I agree, I wouldn't touch that panel with a 10 foot pole. Also, I'd go pull a permit to have my meter exchanged for a meter-main (meter + main breaker). Since there's no main breaker this FPE is probably a Rule of Six/Split Bus panel, making it double trouble. At least the meter-main will take *that* off the table.

If you can access the wires to the crt. You can install a small sub pnl. And main breaker it 30 A and put in a 15 A breaker to the plugs .all plugs in the crt. Will need to be updated down to 15 A.
This is the winner. At first I said "Oh noes, what is hlopez thinking, there's no neutral!" but then OP made clear it's a short run in conduit. Add the neutral if you need to support 120V.

However, my recommendation to OP is to do the subpanel thing, but use a 240V powered air conditioner, and then you don't need a neutral (or even open up the FPE cover). At this point the subpanel can be 2 spaces, no bigger than a disconnect switch. In fact that's a good idea to deter some goober from slapping a 120V circuit in there and just misusing ground for neutral. In fact, buy an accessory ground bar and leave the neutral bar conspicuously empty.

Do adapter cables exist that are fused at 15 amps so it can be used on the larger 30 amp circuit? Any other work around that is safe? I found plenty of adapter cables but none appear to have any sort of a fuse or other overcurrent device in there.
Oh, remember how the saying used to be "you can buy ANYTHING on eBay (and probably shouldn't)"? Now it's "You can buy ANYTHING on Amazon Marketplace". Because Amazon is the new eBay. Precious few items these days are *even from* Amazon; Marketplace is just the eBay crowd who is using Amazon Warehousing (even if you buy the item on eBay). If the seller uses Amazon Warehousing, their crap ships with Prime, which makes people think it's awesome and/or legit.

So yeah, everything on Amazon/eBay/Banggood/Aliwhatever is unsafe crud. Find your friendly neighborhood electrical supply (I'm saying that as a discriminator, find the *friendly* one lol). And get stuff there.
 
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