Got Welder need wiring Advice ASAP!

[Anonymous Poster]

bnixon,
Just put a lincoln buzz box in yesterday thats been sitting around here for years. Sounds like you're having a time of it. The posts so far have pretty much covered your situation, and I guess I just wanted to add my .02.

The welder circuit breaker should be 50 amps, and smallest wire size (copper) should be 8 awg. Do you have 8 or 6 awg wire off of that 60 amp circuit breaker? If you are using 8 awg the breaker will have to be changed to a 50.
The neutral is not required for the lincoln (no 120v requirement) but the ground is required. Is a bare wire from the cable connected to the neutral bar at the house panel? If so, that is your ground wire. The neutral would not be needed if the ground wire is connected. I ran 8/3 w/ ground (black/ red/ white/ bare wire ground) and capped off the white neutral wire at both ends in case it was needed in the future. If the ground wire was cut off, and the white wire is being used as the ground, at least tape it green at both ends to identify it properly.

Regarding the disconnect: the disconnect is required but to have a fused disconnect is not if the circuit breaker feeding it is properly sized for the connected load. In your case the breaker supplying it is larger than the fuse requirement for the machine (referring to the 60 amp breaker at the house panel). The lincoln requires a 50 amp fuse or breaker so if a 6 awg feed with a 60 amp breaker was installed to the welder disconnect the disconnect should have 50 amp dual element time delay (FRN) or equivalent fuses. The cable from the house panel should have a bare wire connected to the ground lugs on the disconnect. Make sure that the lugs installed to the left side of the disconnect are connected to the box electrically (almost looks like a neutral kit is installed instead of a ground kit). The lugs should be screwed right to the metal of the box, not sitting on an insulated stand. Everyone is right on wiring the disconnect; the way it was wired the bottom fuse clips would be hot when you changed the fuses, which could make life a little exciting if you grabbed one, even with the disconnect off.

The Federal Pacific house panel should be replaced. They are a fire waiting to happen should you have a short on a branch circuit and the breaker doesn't trip. The aluminum wiring in the house is also a concern. If you make any connections using that aluminum wire MAKE SURE that you use noalox so that the aluminum connection doesn't corrode and start a fire.

Last but not least it sounds as if you are confused about the use of grounds and neutrals. The neutral wire (in your case the white wire) carries current when a device is connected to one of the incoming phases (the black or red in your case). The ground wire is normally not a current carrying conductor and connects to the chassis of most appliances. If the ground wire was not hooked up on your welder and one of the hot phases contacted the chassis, it would not have a shorting path to trip the breaker and would electrify the housing of the welder. If you touched it and provided a ground path............................ , well you know what would happen /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif.
Just do yourself a favor and be very careful. When working in a hot box it is best to be careful to not provide a grounding path through you. Wear good insulated shoes, never put one hand on a possible ground path (box, water pipe, appliance, etc.) and work in the box with the other, and check to make sure EVERYTHING is off before doing any work. It only takes one time, you know.

Hope this helps.
DaveL

 

[Mrwurm]

Good information DaveL, I am confused about the whole neutral/ground wiring myself. In my main house panel all the white wires and the ground wires are all terminated on the same bus bar which is grounded to the ground rod. If the white wires and ground wires (bare copper) all connect to the same place, then why have both? I don't get it /forums/images/graemlins/confused.gif

 

[Inspector507]

Mrwurm,
Depends on how close the dish ground rods are in relationship to the service ground rod. If they are remote, then you'll be ok. The main reason for a ground rod on a dish is a place to dissipate stray voltage, AKA lightning.

 

[Mrwurm]

Ok, here's another good one. I have two underground feeds that travel about 100 ft to my barn. Both are protected by GFCI breakers in the main box (source) (no breakers in barn). Whenever we have a thunderstorm, both GFCI breakers trip off. Does this occur because they are on a buried line (about 4ft down) or does this occur because they are on a GFCI?

 

[Inspector507]

Could be several reasons for that. Touchy breakers, lines in the ground getting damp and one or more of them has insulation damaged, or just the moisture in the air getting the outlets damp in the barn. A hard rain or even a cool foggy morning will trip a lot of GFCI's due to dampness in the air.

 

[Anonymous Poster]

Mrwurm,
The neutral wire carries current in normal use (completes the circuit). The ground, on the other hand is strictly a non current carrying conductor that provides a path to ground if a failure occurs that could electrify the frame or housing of any piece of equipment, and provides a local ground reference.

The power company transformer converts a higher voltage (7 kv, 13.2 kv, etc.) to 120/ 230 volt single phase to feed your house. They use a transformer to do this. Since the primary winding and secondary winding(s) of the transformer are not connected directly (voltage in the high voltage primary winding induces a lower voltage in the secondary winding) the secondary voltage of the transformer is "floating" at some voltage potential above the ground at the transformer. The neutral is bonded to ground so that the secondary voltage is not able to "float". The neutral is then at the same potential as local ground conditions. Not having the neutral bonded would allow much higher voltages to be present in respect to local ground conditions, and would create some really hazardous situations. The ground wire represents a conductor that is at the voltage potential of local ground conditions (essentially zero). Note that in a situation where a seperate building is sub fed from a house service panel that the code requires a seperate ground conductor, ground rod and segregated neutral and ground bars. This is done for two reasons, first so that if the neutral was broken the ground wire would not become the neutral for the circuit, and second so that the sub fed service is kept at local ground potential through its own ground rod. We could get into soil conductivity and a lot of other things but it gets real technical from there.

Your gfi's probably pop due to a current imbalance induced by a lightning strike. A gfi compares current in both the hot and neutral conductors of a circuit, and trips if the current is imbalanced by more than 5 milliamps (if I remember correctly). When lightning strikes, it is essentially trying to correct a current imbalance between the clouds and ground. The voltage generated by the strike will dissipate over a large ground area, and can induce a current in the underground wiring.

I hope this attempt to explain grounding is correct in all points; I'm not an electrical engineer, just a poor dumb electrician, and I've never had to explain this before. Anybody that has more info please jump in and correct me if I misstated something.

Now I need a beer /forums/images/graemlins/tongue.gif /forums/images/graemlins/tongue.gif /forums/images/graemlins/tongue.gif!!!!
Hope this helps,
DaveL

 

[Mrwurm]

DaveL, that is the best explanation of neutral vs ground. I think I get it, but I will print your response and give it more consideration while in the library.

Also, induced fields have been interesting to me ever since I had a job for a short time doing spot welding. My work station had the hot and ground conductor looped and hanging in a large coil on the wall. Whenever I hit the trigger the wires on the wall would jump and do a little dance. Magnetic field? Induced field? Same difference? I don't know, it was just interesting. /forums/images/graemlins/cool.gif

 

[yooperdave]

Can someone explain exactly by what is meant by feeding the source at the top?

I wired a 200 amp main service to my commercial property in Michigan. The source wires came into the box near the bottom, then continued inside the box to the main lugs at the top. The State electrical inspector did not take issue with what I had done.

I am hoping to do the same with a 100 amp sub panel, by feeding the source wire through the bottom of the box and extending it to the main lugs at the top. This sub box will not be bonded, but I will be running a seperate ground wire to the main service which is bonded.

Does this all sound ok by you electricans out there?

Thanks

Yooper Dave

 

[Anonymous Poster]

yooperdave,
Posts regarding bottom wiring were referring to the disconnect switch mounted by the welder, not the house panel. A knife disconnect is designed so that incoming power is connected at the top. The top connections are covered so that you can't contact a live connection with the door open. Once the door is closed and the switch is thrown on, the knives are engaged, the fuses are hot, and the door interlocks so that you can't open it while powered. As stated before, if you wire incoming power to the bottom connections you will probably electrocute the first poor slob who tries to change the fuses (possibly me) /forums/images/graemlins/blush.gif /forums/images/graemlins/frown.gif /forums/images/graemlins/blush.gif.
If you are going to install a sub panel in a seperate building, the ground rod/segregated neutral - ground bar, 4 wire connection, etc. are required.
Some local codes may vary depending on interpretation by the inspector.
If you are installing a 100 amp subfeed you may want to back feed a 100 amp breaker to power the panel. You normally use a standard 100 amp breaker, and install a kit to lock it in place. It allows you to kill the building quickly if anything were to happen. I'm a control geek, not a construction electrician, so I 'm not sure if this applies, but code requires that a maximum of 6 disconnects are allowed to shut down power in a structure. If you feed a main lug panel without any other disconnecting means in the structure you will be limited to 6 circuits.
Hope this helps. Good luck.
DaveL

 

[yooperdave]

Hi Dave,

I am using a 100 amp main service box as my sub box. This way I have a 100 amp breaker at the sub box and also back at the main 200 amp service.

My building is 2 stories tall, so I thought I would wire the entire second floor off of my 100 amp sub box which is also located at the second floor. I then only have 1 conduit going down to the first level which is feeding the sub box. I was hoping I could use around 12 seperate circuits off of the sub box. The second level is an apartment, while the first level is retail.

Thanks for your help.

Yooper Dave