PSA: Non-fused AC Disconnects

[dmurphy]

When we installed our outdoor Wall Connector a few years ago, our electrician also recommended (and I concurred) installing a non-fused disconnect next to it, since the breaker panel is indoors. Technically, NEC 625.43 requires a disconnect like this for equipment > 60 amps or > 150V to ground. The wall connector is set for 48 amps, and each leg is only 120V to ground so we should be good without one, but still sounded like a good idea.

Well, he installed one of these and all has been good ... until now.

Was outside the other day and got a whiff of burning plastic. My bloodhound-like nostrils led me to the HPWC, and eventually to the disconnect box. Opened it up, only to see this ....

Holy cow! Shut the circuit off immediately (can't exactly pull the non-fused disconnect - it's kinda melted-in-place) and examined what the heck happened here. Looks to me like the fingers that the disconnect slots into are way too thin for a 48A constant draw. You can see one set of fingers was spread open - no spring to them at all - so had a loose connection to the disconnect. Loose connection = resistance = heat = melty disconnect. (Nevermind that surface rust on the contacts - that's because when I cut it out, I threw it on the ground and left it for a few days until the rain stopped.)

Anyway, since NEC doesn't require the disconnect, I decided to cut the wire back to undamaged, and replace the disconnect with a set of Polaris splice blocks. First time using them, but won't be the last. I'm super impressed. Now that it's operational again, once the temperature warms up to the point where I can feel my fingers again, I'm going to clean it up a bit, move that ground block, clean the wires up and apply a little no-ox to it.

Back in business, charging beautifully -- 48A @ 239V. And no plastic-burning smell.

Moral of the story? Keep an eye on these cheap-o disconnects. I'm still pleased with the work the electrician did, but that part is a hunk of junk. I suspect the first time I pulled the disconnect, it bent those fingers on the connector and it's been slowly cooking itself since. Good reminder that we're dealing with a significant power draw here, but these residential manufacturers make MVPs -- Minimum Viable Products. Fast, cheap, reliable - pick two.

 

[holeydonut]

Is was that one of the Eaton 60A Air conditioner non-fused disconnects? It looks like a DPU222RP

DPU222RP | Eaton air conditioning disconnect | Specifications | Eaton

DPU222RP - Eaton air conditioning disconnect, Non-fused pullout, 60A, 120/240V, 10 kAIC, #14-3 Cu/Al 60°C or 75°C, NEMA 3R Galvanized Steel enclosure, 3 hp at 120V, 10 hp at 240V, ANSI 61 gray

www.eaton.com

I had asked for these for my Tesla Powerwalls (already had a 30A OCPD) since I didn't want 3 obnoxious blade disconnects in my garage. But my installer said the DPU222RP would burn up because even though they're rated for 60A, it seems they were only designed for #14-3 AWG Cu/Al... which cannot handle the high amp continuous draw of an EV or Powerwalls.

So I ended up with some Square D DU222RB non-fused... which apparently can use #10-2 AWG Al and tolerate up to 30A continuous.

Square D DU222RB Safety Switch

The Square D DU222RB 2 Pole Safety Switch is a UL listed product with a non-fusible disconnect. Ideal for residential and commercial applications it can be connected with lighting air conditioning and other electrical appliances. The DU222RB has a quick-make and quick-break operating mechanism...

www.superbreakers.com

 

[dmurphy]

Is was that one of the Eaton 60A Air conditioner non-fused disconnects? It looks like a DPU222RP

That is exactly what it was. Serious hunk of junk. Thankfully, our 2nd wall connector ("Hers")

I agree wholeheartedly with your electrician -- it's rated for 60A, but clearly not capable of it safely, at least in my book.

Our wiring is all #8 AWG stranded copper end-to-end, so the issue isn't the wiring.

I had asked for these for my Tesla Powerwalls (already had a 30A OCPD) since I didn't want 3 obnoxious blade disconnects in my garage. But my installer said the DPU222RP would burn up because even though they're rated for 60A, it seems they were only designed for #14-3 AWG Cu/Al... which cannot handle the high amp continuous draw of an EV or Powerwalls.

So I ended up with some Square D DU222RB non-fused... which apparently can use #10-2 AWG Al and tolerate up to 30A continuous.

Square D DU222RB Safety Switch

The Square D DU222RB 2 Pole Safety Switch is a UL listed product with a non-fusible disconnect. Ideal for residential and commercial applications it can be connected with lighting air conditioning and other electrical appliances. The DU222RB has a quick-make and quick-break operating mechanism...

www.superbreakers.com

Good choice. I agree with you - that's a LOT of blade disconnects each of which need a lot (relatively speaking) of clearance. Are the PW's stacked front-to-back? If so, could 2 be connected to 1 disconnect?

The DU222RB is *much* more robust than what I've got, and is exactly what I wish I had. I like the external throw instead of the cheap plastic pull on the Eaton. That said, I'm beyond thrilled with those Polaris splice blocks. They're well insulated, watertight, pre-filled with anti-ox, and just a solid, solid connection. Really nicely done - worth the extra money.

Eaton makes solid products, depending on the division and product line.... but DPU22RP isn't one of them.

 

[holeydonut]

Good choice. I agree with you - that's a LOT of blade disconnects each of which need a lot (relatively speaking) of clearance. Are the PW's stacked front-to-back? If so, could 2 be connected to 1 disconnect?

The DU222RB is *much* more robust than what I've got, and is exactly what I wish I had. I like the external throw instead of the cheap plastic pull on the Eaton. That said, I'm beyond thrilled with those Polaris splice blocks. They're well insulated, watertight, pre-filled with anti-ox, and just a solid, solid connection. Really nicely done - worth the extra money.

Lololol, I hate these stupid blade disconnects... my avatar has a disconnect because at this point I'm resigned to having a bunch. Personally I'd prefer to have none of these hah. I am kind of confused why Eaton would rate the DPU222RP for 60A but then on its spec sheet claim that it can only handle #14 AWG. And yet, your electrician was able to wire in #8 as if it were designed for at least #8.

I agree on the Polaris connectors... very high quality. They also make a cool multi-tap connector that lets you bond dissimilar metal conductors. If you have an electric range or oven in your house, you should check to make sure whoever wired your house didn't use a cheap bullet connector to splice together aluminum and copper. My home was built in the 90s with an all-electric kitchen. Several houses on my street (including mine) had ghetto bullets joining copper to aluminum.

NSI Industries Polaris Black IPL4-3A Insulated Multi-tap Connector - 3-Port Single-Sided Entry for 4-14 AWG Wire Range - Dry Locations - Dual-rated for cooper and/or aluminum - 1.188-inch width, 1.375-inch height, 1.55-inch length - Hex size 1/8-inch

NSI Industries Polaris Black IPL4-3A Insulated Multi-tap Connector - 3-Port Single-Sided Entry for 4-14 AWG Wire Range - Dry Locations - Dual-rated for cooper and/or aluminum - 1.188-inch width, 1.375-inch height, 1.55-inch length - Hex size 1/8-inch: Wire Terminals: Amazon.com: Industrial &...

www.amazon.com

The disconnects are 1 per Powerwall. They are wired kind of confusing because the disconnect on the left de-activates the PW on the right. And the Disconnect on the right deactivates the PW in the left. I actually just wanted a 125A sub panel with 3 breakers in it (one for each PW), but that idea was killed because the installer really wanted to put in non-fused disconnects. I literally had a brand new 125A sub panel and brand new breakers sitting there so it wouldn't even cost the installer anything.

 

[BigNick]

Square D DU323 Safety Switch

The Square D DU323 is a 3 Pole safety switch with a current rating of 100 Amps and a voltage rating of 240VAC. The DU323 has a surface mounting type and it is used for general purpose indoor applications.

www.superbreakers.com

I've got one of those, and after reading this post, I opened it up to look inside.
No melting, no smells, nothing out of the ordinary.
My HPWC is on a 100A-rated circuit but has never been used at > 40A. When I had it installed, I had planned on eventually getting a "dual charger" car that could charge at 80A/72A, now they all max out at 48A/32A.

 

[qdeathstar]

That is exactly what it was. Serious hunk of junk. Thankfully, our 2nd wall connector ("Hers")

I agree wholeheartedly with your electrician -- it's rated for 60A, but clearly not capable of it safely, at least in my book.

Our wiring is all #8 AWG stranded copper end-to-end, so the issue isn't the wiring.

If you are drawing 48 amps continuous you need to use #6…. The wire need to be rated at 125 percent of the continuous load.

The wire does look like number 6 though; hard to tell from the picture. To me it looks like it started burning from the lug. That is a symtom of an undertightened lug.

What does the flex going off to the right go? It isn’t in the first picture

 

[dmurphy]

Lololol, I hate these stupid blade disconnects... my avatar has a disconnect because at this point I'm resigned to having a bunch. Personally I'd prefer to have none of these hah. I am kind of confused why Eaton would rate the DPU222RP for 60A but then on its spec sheet claim that it can only handle #14 AWG. And yet, your electrician was able to wire in #8 as if it were designed for at least #8.

When it says AWG #14-3, it means it can handle anything size wise from #14 down to AWG #3. As your says, #10 AWG down to #2 AWG.

So it's designed to handle the cable size OK, but I think the blades for the disconnect itself are too thin. They pass UL and CSA listing, but that doesn't say much these days (sadly.)

I agree on the Polaris connectors... very high quality. They also make a cool multi-tap connector that lets you bond dissimilar metal conductors. If you have an electric range or oven in your house, you should check to make sure whoever wired your house didn't use a cheap bullet connector to splice together aluminum and copper. My home was built in the 90s with an all-electric kitchen. Several houses on my street (including mine) had ghetto bullets joining copper to aluminum.

Our home dates back to '68, so everything here is copper. We got lucky and missed the aluminum trend by a couple years. The oven is gas, so there's only a simple 120V outlet for the electronics.

We had a panel upgrade done about a dozen years ago, so we've got 200A service and a Siemens panel. Originally it was Federal Pacific, so glad that's long gone.

Really glad we don't have aluminum wiring - that can be an absolute nightmare. These Polaris blocks are good for that as well - they're rated for dissimilar metals.

NSI Industries Polaris Black IPL4-3A Insulated Multi-tap Connector - 3-Port Single-Sided Entry for 4-14 AWG Wire Range - Dry Locations - Dual-rated for cooper and/or aluminum - 1.188-inch width, 1.375-inch height, 1.55-inch length - Hex size 1/8-inch

NSI Industries Polaris Black IPL4-3A Insulated Multi-tap Connector - 3-Port Single-Sided Entry for 4-14 AWG Wire Range - Dry Locations - Dual-rated for cooper and/or aluminum - 1.188-inch width, 1.375-inch height, 1.55-inch length - Hex size 1/8-inch: Wire Terminals: Amazon.com: Industrial &...

www.amazon.com

The disconnects are 1 per Powerwall. They are wired kind of confusing because the disconnect on the left de-activates the PW on the right. And the Disconnect on the right deactivates the PW in the left. I actually just wanted a 125A sub panel with 3 breakers in it (one for each PW), but that idea was killed because the installer really wanted to put in non-fused disconnects. I literally had a brand new 125A sub panel and brand new breakers sitting there so it wouldn't even cost the installer anything.

View attachment 766032

Even out of order, that's a beautiful installation! Wish I had the wall space in our garage for such a thing. Or, to fit my car in. Can't do that either - the back corner was carved out by the last owner into a sun porch, so it's no longer deep enough to fit anything except possibly a Fiat 500. And that's a big 'ol maybe.

If/when we do power walls, they're going to be an outdoor install.

 

[dmurphy]

If you are drawing 48 amps continuous you need to use #6…. The wire need to be rated at 125 percent of the continuous load.

The wire does look like number 6 though; hard to tell from the picture. To me it looks like it started burning from the lug. That is a symtom of an undertightened lug.

What does the flex going off to the right go? It isn’t in the first picture

You're right - it's #6; typo on my part. I just double-checked. Lugs seemed tight, but again I'm not an expert, just a homeowner.

The flex goes to an L5-30 (120V/30a) I installed for a travel trailer. *THAT* is the 8AWG... that I typo'd above. I added that after the original install. It's a separate circuit; It's only sharing the conduit with the EVSE circuit - that's a 1" so I had enough fill space left instead of running another.

Was grateful to have the L5-30 as I could use that with the Tesla Mobile Connector to charge while the wall connector was out of service.

 

[Rocky_H]

The wall connector is set for 48 amps,

Our wiring is all #8 AWG stranded copper end-to-end, so the issue isn't the wiring.

If that's 8 gauge copper, that absolutely is a problem for a 60A circuit. That should have melted something much sooner if that's the case.

You're right - it's #6; typo on my part. I just double-checked.

If that's 6 gauge individual wires in conduit, that would be OK for a 60A circuit. If it's 6 gauge Romex, it wouldn't be (despite what this guy above I have blocked says).

 

[qdeathstar]

If that's 8 gauge copper, that absolutely is a problem for a 60A circuit. That should have melted something much sooner if that's the case.

If that's 6 gauge individual wires in conduit, that would be OK for a 60A circuit. If it's 6 gauge Romex, it wouldn't be (despite what this guy above I have blocked says).

Lol. Look at the pictures bro. The breaker doesn’t determine wire size.

 

[dmurphy]

If that's 8 gauge copper, that absolutely is a problem for a 60A circuit. That should have melted something much sooner if that's the case.

If that's 6 gauge individual wires in conduit, that would be OK for a 60A circuit. If it's 6 gauge Romex, it wouldn't be (despite what this guy above I have blocked says).

Yes, #8 is a typo - I can't go back and edit anymore. It's definitely #6. Not #6 Romex though - it's THWN-2 in a 1" conduit.

 

[holeydonut]

When it says AWG #14-3, it means it can handle anything size wise from #14 down to AWG #3. As your says, #10 AWG down to #2 AWG.

So it's designed to handle the cable size OK, but I think the blades for the disconnect itself are too thin. They pass UL and CSA listing, but that doesn't say much these days (sadly.)

Hmmmm, I wonder why the installer said he needed a different non-fused box for my Powerewalls. While your disconnect may have had a problem, it should be ok for up to 60A if properly wired. I told Sunrun I definitely did not want any stupid ass levers if I could avoid them. And I ended up with 4 stupid ass levers (there's another huge single disconnect on the outside of my garage).

 

[fiehlsport]

I installed one of these disconnects for an AC unit and the blades were VERY loose. I pinched them closed a little more, which fixed the issue and made a very tight connection when it was pushed back in.

Sounds like yours came loose from the factory as well. Definitely good you deleted it - it's totally unnecessary for this application since there's a breaker on the other end.