Breaker box & breaker type help

[Shaun @ Tru6]

New shop breaker box, what can you tell me about it?

30A breaker is too small for my compressor. Also why does the one outlined have the neutral going into the breaker? In my old building, neutral went to a buss bar.

Compressor is 7.5 hp motor so I would need a 60A.

Hoping to prevent a service call tomorrow.

[masraum]

I'll preface with "I'm not an electrician." Looks like a 3 phase breaker. If I had to guess, someone cut some corners when they wired it up. But before you do anything, wait for someone who stayed in a Holiday Inn Express last night to comment.

[rockfan4]

Well, that's a 3 phase box, so you're going to get about 208v going across a pair.

Why is there a white wire going into a breaker? Because it wasn't run by an electrician would be my answer. If you've got a regular single phase outlet on the other end of that run, you're in for a surprise when you plug something in.

[masraum]

Originally Posted by rockfan4

Well, that's a 3 phase box, so you're going to get about 208v going across a pair.

Why is there a white wire going into a breaker? Because it wasn't run by an electrician would be my answer. If you've got a regular single phase outlet on the other end of that run, you're in for a surprise when you plug something in.

LOL!
First thing that came to mind when I read your post.


The second thing that popped into my head.

[Shaun @ Tru6]

Originally Posted by rockfan4

Well, that's a 3 phase box, so you're going to get about 208v going across a pair.

Why is there a white wire going into a breaker? Because it wasn't run by an electrician would be my answer. If you've got a regular single phase outlet on the other end of that run, you're in for a surprise when you plug something in.

The secondary box across the shop that this breaker goes to has an on/off lever, the white wire is not connected at the ON side which feeds an outlet for a single phase lift.

[peppy]

We have 3 phase square d panels like that, but there is a main disconnect in the box. We do not have neutrals on 3 phase equipment. Just 3 hots and a ground are what we have and that white wire is probably be the high leg of the 3 phase.

After looking at the panel you probably don't have a high leg, every third breaker slot would have the higher voltage.

[Scott Douglas]

The cost of a service call will soon be forgotten when you can use any plug without worry of electrocution.

Did I tell you guys the story of my cousin who was fishing in an aluminum boat on a private lake that had a bridge over it?
He reached up and touched the bridge and was electrocuted. Someone didn't wire the lights on the bridge correctly.
He was only 10 years old.
Part of the reason I don't mess with electrical stuff like this. It can and will kill ya if given the chance.

[908/930]

Will start with I'm not an electrician. But thinking somebody possibly ran out of #12 blue wire or they needed 3 phase power where that ends up and just reused the white. Pretty dangerous if somebody assumes that white is a neutral wire at the other end. At least put blue tape on it to identify it.

60A for 7.5hp? Sounds high, is that motor single phase?

[greglepore]

Originally Posted by 908/930

Will start with I'm not an electrician. But thinking somebody possibly ran out of #12 blue wire or they needed 3 phase power where that ends up and just reused the white. Pretty dangerous if somebody assumes that white is a neutral wire at the other end. At least put blue tape on it to identify it.

60A for 7.5hp? Sounds high, is that motor single phase?

This more or less. Someone didn't have correctly colored wire for 3 phase and used standard 12/3 intended for 2 phase use. Yeah, blue tape on it, both ends.

[schwarz633]

Probably used 10/3 romex, or some type of cable for that 30A 3-phase circuit. That being the case, you have to use the white wire for one of the 3 "hot" conductors. That's allowed, but the white wire should have been marked with tape or paint on both ends.

[908/930]

If your compressor motor is single phase you have a snag, unless you have a 3 phase to single phase transformer. But a 3 phase motor would be a better choice.

[Bill Douglas]

On a more positive note () three phase is good. It's expensive to get put in so great that someone else paid for it. And it all looks very tidy too.

[billybek]

Originally Posted by 908/930

Will start with I'm not an electrician. But thinking somebody possibly ran out of #12 blue wire or they needed 3 phase power where that ends up and just reused the white. Pretty dangerous if somebody assumes that white is a neutral wire at the other end. At least put blue tape on it to identify it.

60A for 7.5hp? Sounds high, is that motor single phase?

This. Here it would pass inspection if both ends were taped to identify it as one of three phases.
60 amps isn't all that high to handle the inrush at startup on a single phase compressor.
If three phase is available, I would change the motor to three phase if it the original were to fail.
The wire size would need to be sized to the breaker. #6 for 60 amps I think.

[Pazuzu]

Originally Posted by peppy

We have 3 phase square d panels like that, but there is a main disconnect in the box. We do not have neutrals on 3 phase equipment. Just 3 hots and a ground are what we have and that white wire is probably be the high leg of the 3 phase.

After looking at the panel you probably don't have a high leg, every third breaker slot would have the higher voltage.

It's a basic 5 wire 3-phase box. Allows for the standard 3-phase power, plus 120V single phase by combining one of the legs with a neutral and a ground. Let's you have 120V outlets without any extra transformers. Also allows 208/3 and 120/1 and 240/1 all in the same machine without a transformer.

[jyl]

Skinny wire for 30A, isn’t it?

[Shaun @ Tru6]

So much to digest here, thank you. I'll put together a more inclusive description of details a little later on.

I can say now the compressor is 1.5 years old, an Atlas Copco screw, single phase 230V that I have a buck boost transformer for. I can ask how much a 3 phase motor is. The compressor was 5 figures so I need to keep it.

I was told this place is single phase 208V.

[schwarz633]

208V would indicate a 3 phase service. 120V between each hot leg and neutral, 208V between the hot legs. If you take a voltmeter and measure 208V from A>B, A>C, and B>C, I would say you've got 3 phase. Is this the same service that you were jacking around with the loose connection outside?

[MBAtarga]

Originally Posted by Shaun @ Tru6

I was told this place is single phase 208V.

Someone either lied or was confused.

[70SATMan]

Shaun, where’s the main three phase disconnect for that box? Is it a blade lever box next to or is it disconnected only by a main breaker in a main panel elsewhere? You need to know the service limit feeding your box as well.

[Shaun @ Tru6]

Originally Posted by MBAtarga

Someone either lied or was confused.

I'm going with confused. He was very nice, I don't think any malice or trickery was intended.