4 prong to 3 prong twist lock questions

[TommyTbar]

So I have a control panel for my system that has a 4 prong 240v male plug for powering the panel

View attachment ImageUploadedByHome Brew1451538160.880986.jpg

But at the brewery I work at we only have these receptacles for 240v single phase

View attachment ImageUploadedByHome Brew1451538296.981428.jpg

So my question is could I rewire the male 4 with a 3 prong twist lock or make an adapter with another section of wire?

We have the female plug receptacles that work with the 4 prong male but they are 3 phase. From what I read I shouldn't plug my panel into a 3 phase outlet...

Any insight would be appreciated thanks!

 

[FuzzeWuzze]

So I have a control panel for my system that has a 4 prong 240v male plug for powering the panel

View attachment 326431

But at the brewery I work at we only have these receptacles for 240v single phase

View attachment 326433

So my question is could I rewire the male 4 with a 3 prong twist lock or make an adapter with another section of wire?

We have the female plug receptacles that work with the 4 prong male but they are 3 phase. From what I read I shouldn't plug my panel into a 3 phase outlet...

Any insight would be appreciated thanks!

I first need want to make sure you really mean 3 phase outlet, and not 3 wire(dual phase) 240V...they are vastly different. So it alters the answer you need.

Typically 3 phase is only used in industrial scenarios which i suppose a brewery could have it.

 

[idiotsinc]

Can't tell anything from your plug but all my equipment is L630 (which you show in your second picture). My recommendation is to contact the builder of your panel. I can't imagine any reason you need a 4 contact plug with a 240v system.

 

[BrunDog]

Can't tell anything from your plug but all my equipment is L630 (which you show in your second picture). My recommendation is to contact the builder of your panel. I can't imagine any reason you need a 4 contact plug with a 240v system.

If that system uses any 120VAC via a neutral path, then you certainly do. Hot1, Hot2, Neutral, Ground are the lines for a 4 conductor plug/system. In a three conductor, it is Hot1, Hot2, and Ground - in this case everything is powered by 240VAC.

Like Fuzze said... 3 phase is not 3 wire and is certainly not compatible with residential wiring.

 

[itsnotrequired]

i'd be shocked (ha ha) if an l6-30 was used on a three-phase system as a three-phase connection. it would need to be a delta system with no neutral. the l6-30 is really geared toward single-phase, two-wire systems (two hots and a ground).

to the original question, you may be able to replace your plug with a l6-30p but if your panel has any 120v loads (e.g. contactor coils, indicating lights, etc.), they systems will not be compatible. the fact that your panel has a 4-prong plug implies there are indeed 120v loads.

 

[ScrewyBrewer]

I highly recommend that you consult a licensed electrician before attempting any wiring modifications yourself if you are unsure.

Single Phase:

Controllers can be connected to 240v lines using just 3 wires, but controllers wired with 4 wires use GFCI breakers on the circuit.

There is an article posted here that may be helpful to you for use as a reference.

 

[ajdelange]

So I have a control panel for my system that has a 4 prong 240v male plug for powering the panel

But at the brewery I work at we only have these receptacles for 240v single phase

So my question is could I rewire the male 4 with a 3 prong twist lock or make an adapter with another section of wire?

Stop! I don't mean to be unkind but the fact that you ask this question says that you need the help of a professional electrician before you start a fire or electrocute yourself (or someone else). If you were to put a 3 wire plug on your 4 wire cord you would either have to just not connect one wire or connect two wires together. Neither of these is a good idea.

Your equipment requires +120, -120, neutral and protective ground. That is why you have a four pin plug. Your equipment must be plugged into an outlet which provides all four of these. Your three pin outlets provide only the two phases (+120 and -120) and the protective ground. You must replace them with 4 pin outlets that provide all 4 connections. This will probably mean pulling a new cable (red, black, white, green) from the panel to the outlet. As an alternative you can rewire your equipment by installing a 240V to 120V transformer in it and deriving the 120V needed by whatever it is that needs it from that transformer. This may be simpler than pulling a new cable. Call an electrician.

We have the female plug receptacles that work with the 4 prong male but they are 3 phase. From what I read I shouldn't plug my panel into a 3 phase outlet...

There are plenty of cases where you do connect single and bi-phase equipment to three phase systems. In fact the ±120 wires in your 3 wire outlets are probably 120 and 120e^j2π/3 (you can confirm this by measuring between the bent slot and either if the other slots and then between the two other slots). If you get 120 between the L slot and the 'straight' slots and 208 between the others this is the case and you could indeed connect to the 3ø outlet (provided that it is 120Y/208) but I don't recommend doing this yourself unless you fully understand what is going on (and it is indeed 120Y/208). It would be best to wire a 120Y/208 drop (of sufficient capacity) with an outlet compatible with the plug on your equipment. If you have 4 pin 3ø outlets it sounds as if things are ∆ connected (no neutral). This would preclude this approach. Call an electrician.

Any insight would be appreciated thanks!

Get an electrician in there.

 

[TommyTbar]

I first need want to make sure you really mean 3 phase outlet, and not 3 wire(dual phase) 240V...they are vastly different. So it alters the answer you need.

Typically 3 phase is only used in industrial scenarios which i suppose a brewery could have it.

Thanks for the reply, yes we have 3 phase power at be brewery. Some of our CIP pumps run on 3 phase some on single. The 3 phase has the same type outlet compatible to my panel. Unsure if I should plug it in.

 

[TommyTbar]

Stop! I don't mean to be unkind but the fact that you ask this question says that you need the help of a professional electrician before you start a fire or electrocute yourself (or someone else). If you were to put a 3 wire plug on your 4 wire cord you would either have to just not connect one wire or connect two wires together. Neither of these is a good idea.

Your equipment requires +120, -120, neutral and protective ground. That is why you have a four pin plug. Your equipment must be plugged into an outlet which provides all four of these. Your three pin outlets provide only the two phases (+120 and -120) and the protective ground. You must replace them with 4 pin outlets that provide all 4 connections. This will probably mean pulling a new cable (red, black, white, green) from the panel to the outlet. As an alternative you can rewire your equipment by installing a 240V to 120V transformer in it and deriving the 120V needed by whatever it is that needs it from that transformer. This may be simpler than pulling a new cable. Call an electrician.

There are plenty of cases where you do connect single and bi-phase equipment to three phase systems. In fact the ±120 wires in your 3 wire outlets are probably 120 and 120e^j2π/3 (you can confirm this by measuring between the bent slot and either if the other slots and then between the two other slots). If you get 120 between the L slot and the 'straight' slots and 208 between the others this is the case and you could indeed connect to the 3ø outlet (provided that it is 120Y/208) but I don't recommend doing this yourself unless you fully understand what is going on (and it is indeed 120Y/208). It would be best to wire a 120Y/208 drop (of sufficient capacity) with an outlet compatible with the plug on your equipment. If you have 4 pin 3ø outlets it sounds as if things are ∆ connected (no neutral). This would preclude this approach. Call an electrician.



Get an electrician in there.

Thanks for all the information. I guess I should of asked our electrician last time he was in. I am not at all well versed with this stuff but thought it might me a simple fix, I can see why combining the neutral and ground is not a good idea.

Thanks everyone who chimed in

 

[raouliii]

So I have a control panel for my system that has a 4 prong 240v male plug for powering the panel
....
But at the brewery I work at we only have these receptacles for 240v single phase
.....
So my question is could I rewire the male 4 with a 3 prong twist lock or make an adapter with another section of wire?

We have the female plug receptacles that work with the 4 prong male but they are 3 phase. From what I read I shouldn't plug my panel into a 3 phase outlet...

Any insight would be appreciated thanks!

Your control panel appears to have a NEMA 14-30P plug. The NEMA 14-30 configuration should NOT be found in a 3phase system. Let's hope you CAN'T plug your panel into the 3phase system at work. 3phase, four wire receptacles should be either NEMA 15-##R or 18-##R and would not allow a 14-30P plug to be inserted.

 

[idiotsinc]

I just realized that the comments I made earlier about using a L630 plugs was because I'm working on upgrading my electric kettle and thinking about the cord coming out of my control box and to my heating element. Was not thinking about the fact the plug is actually powering Tommy's control box.