Residential 3 phase meter panel combo (revisited)

[@Sparky-ww5re]

High leg Delta with an open delta, is fairly common in rural areas especially farms. Typically used when the majority of the loads are your typical 120/240V single phase, along with a few three phase loads, such as augers, conveyer, grain dryers and similar large motors. You can identify this if you see two transformers, one being much larger, this is the lighting transformer, the smaller one is the power transformer. Utility's will do this when the full capacity of a closed delta is not warranted. If you see a three phase panel and every third slot is blanked or a two- or three pole breaker, this is a very good indicator of a high leg service. Two of the tree phases to neutral will supply 120 volts, the other is 208 to neutral, which is (almost) never used, and you have to be aware of this when hooking things up. The stinger leg is supposed to be orange, but always verify with a meter, never trust colors.

[@3beltwesty]

Nice Video. Few know about these older 3 phase breakers in single phase boxes. The bulk of the installs were done in the 40's, 50's 60's and early 70's. At 1:24 Here I have a 3 Pole Delta Breaker too. They were allowed up to about roughly 1978 by the NEC for new installs. One can replace a faulty breaker but not use them on new or retrofits. The breakers are super rare and command a hefty used price if you can actually find them. A used 3 phase Delta breaker can cost more than all the new to code new stuff! ie the Square D break of mine is never on ebay even after a decades search. A few sit on shelves as used pulls going for a grand or two. My old 60 amp 3 phase delta breaker feeds a single 5 ton 3 phase AC unit and sits in a single phase Square D 225 amp single phase box. My wild cat 208 Volt stinger leg comes down hot right from the meter and goes direct to the delta breaker, thus fun to have this un fused un breakered number 4 wire to watch while replacing the delta breaker. That is why they are sort of no longer used in new installs. If that hot stinger leg touched the panel then one has a direct short that is only current limited by the Pole Transformers Impedance and line from goose neck to Pole . One would have a giant flash, arc fault and the transformers fuse would blow. One might get blinded by molten metal of the arc, or worse. Thus the proper way to replace a delta breaker is to pull the meter out if the wild cat high legs stinger wire has ANY chance of contacting another phase or ground or neutral.

[@MrShockman10]

I realize you have presented this video on here in 2013. I find it very interesting that a delta system three phase for residential use. You had pointed out C phase was your high leg. Here where I live in Illinois a commercial building using a delta system we would put the high leg on B phase mark it with orange tape per code. We would still have to be careful C phase also could be used for the high leg that would depend on installs that were existing. Most systems that I have work with are 277/480 3 phase in commercial buildings. We do in residential use 120/240 volts single phase. Thanks for the posting on here.

[@3beltwesty]

The meter socket in Illinois uses the right side ( in the meter socket box) as the C leg for wildcat leg in the meter's box. This is required in all 3 phase meters in the USA because of how the meter works. ie that is how the utility company has to wire the meter socket. THEN this "C phase wire" connects as the B phase when in the circuit breaker box.

[@sonnyrico8721]

it already wire up for 3 phase 1 lag is 120 next 2 lag is 120 and 3 lag is a wild lag it more I have to make 208 V help !

[@sonnyrico8721]

this is a market I need to hook up a the entrance fan it it 208v not 240 !

[@adamwise1790]

In pa the high leg goes on the b phase and the right side of the meter socket which would be c phase also marked orange out of mast or underground feed

[@adamwise1790]

Delta systems aren't as popular as 3 phase wye with a built in neural most commerciAl buildings have 480 277coming in and steps down to 120 208 for everything else

[@atomscott1919]

I have a several customer homes in Florida using Open Delta 3-Phase 240 Volts. It is used for the A/C units and Well Pumps, There is also a Wall mounted Hot-Air Hand Dryer in the Bath that uses the 208 Volt wild B Phase and Neutral.

[@BVN-TEXAS]

Now what’s crazy is a corner ground three phase system.

[@infl]

I wish we had three phase at my house... God damn capacitor motors

[@BVN-TEXAS]

I’ve seen it several times here in Houston. It’s not uncommon to see when a residential street backs up to a street that’s commercial and on three phase.

[@ericfox7234]

I've seen it before in Ocala fl ,as you said for the ac comp

[@cabcorner1]

I have worked on a few 3 phase residential services but never a 120-240 delta high leg . I'm not sure I like the 3 phase Delta panel on a house. Someone might rearrange the breakers or take advantage of all the spaces on "B" phase . Those Delta breakers are cool though, I have never seen those before .

[@Sparky-ww5re]

I've heard and read about delta breakers but never seen one before. My understanding is they were prohibited in the 1978 NEC, and were available for a short time afterwards in the early 80s for replacement use, and were marked FOR REPLACEMENT USE ONLY. They were called out as a shock hazard because the 208V high leg can backfeed through the equipment onto the bus bars of the panel if the delta breaker is turned on. This configuration was most common in the 1950s and 60s, for a 4 or 5 ton air conditioner, because when home air conditioning was in it's infancy there were many models on the market that were 240 volt 3 phase because they were more reliable and more efficient than a single phase unit. Most of these old 3 phase condensers have been long replaced with a high efficiency 240 volt single phase unit, and the three phase service is no longer needed.

[@AdCurves]

3 phase is all we have in oz so your haters are completely wrong and you are very right

[@electricalindustry]

These units are more efficient to operate. 3 Phase is VERY random in certain areas of the city.

[@alllink3823]

Nice dear

[@IAhawkeye1983]

Are the air conditioners that are installed in that area more powerful than those installed in northern climates and is that the reason that 3-phase is common in residential settings. Around here (Massachusetts) there are no 3-phase residential installs (except for large apartment complexes).

[@josuadalisay2457]

nice one.. I had a different situation here. I have a 3-phase Panel with 100AT,3P as Main CB and had 6-branches, 50AT, 3P feed by a 3 phase Step-Down transformer 440/230v. The problem is, the equipment that arrived is 230v -1 phase. Replacing the 3-pole 50AT by 2-pole will cost me a lot. Is it possible to use only the 2 terminals of 50AT ckt breaker as ckt protection for single phase loads? what is the effect on the other terminal/bus that is not used? using Phase AB for ckt 1,2,Phase BC for ckt 3,4 and Phase AC for ckt.5,6 Assuming the same loads. thanks

[@mobilechief]

I have seen it many times, in VA

[@TradieTrev]

Very interesting my friend! It makes perfect sense considering the 120 line volts. I'd love show you a Aussie 3phase setup (which differs also in my neck of the woods) Quite surprised they haven't updated the USA code for "Safety Switches/RCD's", every circuit in our households are required to have them, pending specific application/situation.

[@millermatic140]

So the air compressor that was gifted to me ended up being a three phase 208-230/460 volts. The guy said he had it wired with a 220 and his building was a B Phase and his guys told him it can be wired to run differently wiring through the relay wires which are all tied together. One electrician told me if my home is and most likely is a single phase then it will not be able to run. Another electrician told me today as long as the motor has a low and high voltage it is possible. It’s a shame because this is a very good old compressor. Can someone flat out tell me the truth? I heard also that I need a converter in or to ONLY do this three phase to single phase conversion

[@jacquelineheaton8463]

3 PHASE METER WIRES FROM POLE WHAT SIZE FOR 200AMP? I KNOW 240V 2/0 COPPER 4/0 AL BUT I KNOW NOTHING ABOUT 3 PHASE. SRRY CAPS STUCK ON

[@windoes98se]

is that some cloth covered knob and tube stuff in the old panel?

[@liam101300]

im a sparky here in australia we have 240v single phase and 415 three phase standard if i was the i would call that two phase what would you call it

[@icadolli]

I have this same set up but my ground have voltage on it what will cause this How can I fixed this issue

[@abbynormal543]

I have a customer who wants to change the three-phase overhead to a two-phase underground panel here in Phoenix Arizona this would just require a new two phase 200 amp panel correct?

[@electricalindustry]

Ronald Raines First check with the power company that services the area to see if they will do this for you.

[@ОляП-д4х]

👍👍

[@sancop]

How do I wire stove (4 wire) on 3 phase (120, 208, 120)

[@playnationtoday]

Sandra Coppedge hire an electrician that knows...it should be easy for a qualified professional

[@mkirankumar8287]

How to 3 phrase transformer power of

[@coreyfontaine2181]

I believe you have a 3 phase, 4 wire 120/208, usually Max amps is 200. If it was a 3 phase, 3 wire, delta system you would not have a neutral. SEE electrical code book 6-402(2). Two of the sinosodal waves on your 3 phase are the same, where as in a true 3 phase system they are not.

[@3beltwesty]

It is a 4 wire high leg Delta 3 phase system. 4 wires, 3 hots 1 neutral. The 3 hots are 240 line to line. The Neutral is in the center of one pair so one has 120/240 single phase too. The 3 hots are 120, 120 and 208 to Neutral in this 3 phase scheme.

[@sancop]

Would love some help. How do I contact you?

[@electricalindustry]

What are you needing,in general?

[@sancop]

Electrical Industry Network, we have 3 phase power in commercial building converted to a house. Never understood that the “A, B, C” mattered until we had 3 oven range control units die in one year. Now researching! What confuses me is my 3 wires come in but the jumper (what appears to be the “A”) is on the right, not left. Is that a normal thing?

[@electricalindustry]

A,B,C maters in motor rotation.If this has been a continual problem you should have a electrician come in and do some troubleshooting tests to find the problem.

[@emilyxuan590]

Sealing screw manufacturer

[@daltonreece978]

Very wrong