Electric to shop

I came across a real deal on direct bury 4/0 RHH or RHW-2 type mobile home aluminum feeder cable. No problem with code. I am thinking of running it from the temp panel for now to a tractor shed. The problem is running it back out of the shed to the shop. I inherited the 200 amp seimans panels for each, so I'm set there and am trying to use what i have. They make a 200 amp breaker (Seimans panel) but the lugs are too small for 4/0 to connect, to run it out of this panel to the shop. Can someone suggest how to connect it or if there are adapter lugs that will fit the breakers? A website on lugs would help. Other problem is this cable has an extra ground (4/0 4/0 4/0 and 2/0), if i use it where does it connect? I was going to put one on each neutral bus-no problem on a lug for the 2/0 to neutral.

My concern is voltage drop, aluminum wire with high water table, and making the connections. After looking at the temp service i notice the power co uses aluminum cable, but they have transformers to boost voltage. Can someone tell me how to figure voltage drop? I am considering the 4/0 aluminum figureing that size will carry the most current and lose less and the price is 1/3 of copper. Is 350 feet too far with 4/0 aluminum run to two service panels?

My shop is about 300 feet from my house, and i beat my head on the wall trying to think of every way to get "good" power out there, the cheapest way.

What ended up being best for me, was to get a second meter loop, (and can) and have a seperate 200 amp service put to it. Now my shop has all the power it needs, and when my big compressor is running and i'm welding at the same time, the lights in the house don't pulse!!

I paid them to go under ground the last 80 feet or so ($3.50 per foot) because of safety issues, as i have a pond next to the shop.

All the over head wire and one pole was free, i only had to pay for what they put under ground.

Robert

You are making this harder than it is.

Your power company engineer is telling you the straight scoop. But, you have to 'read between the lines' as to what he isn't telling you as well.

The Power Company services you to the meter; that's where they stop.

From the meter on, you are totally responsible for the electrical setup and for it being up to code. And, it usually has to be inspected by the local authorities.

Get yourself a qualified electrician, tell him your requirements and show him what supplies you already have.

He will then decide if your wiring/equipment is up to code or not and will promptly grab that feed on your side of the meter, trench in the necessary/proper wiring & conduit to your outbuildings and will install the proper service panel for what you needs are.

Further, he'll more than likely, have it all done/up and running before lunchtime.

Just my view and stated as such,

Allan

Your wire does not have an extra ground. I suspect most 240V single phase connection would use the 4/0, 4/0 and 2/0 with the 2/0 as the ground ( neutral ). The wire you got a deal on is meant for a three phase power system. NBD, you just have an extra conductor you don't need.

I was talking with my power company installation person yesterday. He says people are burying their wire in some kind of sewer pipe that $20 per 100 feet. High water table don't seem like a real problem. Rocks and driving heavy trucks and tractors around the farm sounds like a problem.

When you say they are running it 1500 feet from the street I am confused. Is there going to be a step down transformer at that point? If so then your just running 350' to the shop, not 350 + 1500.

You should still be concerned about voltage drop. My electric company installation fellow gave me a book with a table in it saying how many amps you can draw on a given size wire so many feet long with only a 3% drop. But it's a little more complicated than that because you are going to have branch wiring from the breaker panel that you are need to add that in too.

There are voltage drop calculators around the web. I see links to them in the breaktime forum at www.taunton.com, they publish Fine Homebuilding and other magazines.

An auto transformer or a buck and boost transformer might be a solution too.

I did not really feel my power company engineer was an engineer. He thought I might need to talk with an electrician. You might need an electrician or better yet a real engineer.

Where can i find out about the auto transformer or a buck and boost transformer?

I want to learn as much as possible on the subject--regardless. A trip to the library is a good idea and it's great to have everyones input. Thanks.

It looks like the 4/0 cable would provide 100 amps with a 3% drop using an online calculator just figureing the distance.

I know people who have run above ground cable in sealed pipes underground and they failed. I think the heat from current flow forms condensation in the pipe due to the cooler soil and eventually it oxidizes and loses conduction.

Link

Buck and Boost starts on page 19. Basically it acts as a step up transformer. You might have 200V on the input and 240V on the output.

You say: "I suspect most 240V single phase connection would use the 4/0, 4/0 and 2/0 with the 2/0 as the ground ( neutral )."

I do not think so! The neutral wire & the ground wire are _NOT_ the same. It is easy to make electricty work without the ground wire; and it is east to make the ground wire carry the neutral load. Works just fine. But it totally defeats the point of the ground wire, and sets up a dangrous condition.

These days, I believe you need to run 4 wires from your meter/ pedistal box*, or 4 wires from your main panel if that's all you have, to every other sub-panel.

You need the 2 hot wires, both 120v. Together they give you 240v.

You need the neutral wire, which is the return path for either of the hot wires to form a 120v line.

And, for the past several years, you need a seperate ground wire to make everything safe. Likely this is the lighter wire of the 4, but I'm not sure. This wire connects to all bare metal of all your appliances; all the metal boxes in all your wiring; all the round 'third leg' connectors in all the outlets; and so on. This wire gets isolated from all other wires except one location - the main panel (or disconnect) it gets tied onto the same ground bar as the nuetral wire - only this one place. But, it never ever should be confused with the nuetral, or interchanged with it, or be connected to any other neutral buss anywhere else in the system. (With an asterik for certain out-building setups on a farm site where no plumbing is shared, etc. - bet that is wiped out in the '05 code.)

In a good world, this ground wire will never ever be used. Ever. Terrific. You'll never know it was there, or it was wired wrong, or is missing.... BUT, if there ever is a problem in your wiring, this wire will save your life or your building from burning down or your kid's life or your grandkid's life 40 years from now....

But, _only_ if you wire it up properly! It needs to be isolated from the other wires, except at that one connection point in the main panel. Which, unfortunately, makes it look 'just like a neutral' wire. But it shouldn't ever be confused as one.

In days gone by, each panel or building had it's own ground rod (still do...) and this was used for the ground wire, not all run back to the main panel. But they found that electricity was using water pipe & other connections between buildings and defeating the whole safety point of the ground system - as well as too much resistance in the earth so you or I would still get a big jolt. So now to make it work, you need the ground to be a seperate wire all the way through, with only one terminal connection in the main panel.

Anyhow, that's my simple understanding of it. I could easily have some stuff wrong, so don't rely on me - find out the real deal from a good source.

No one really commented on the aluminumn wire either - it makes good enterance cable, but it does not clamp well to lugs. It likes to change size as it heats & cools, and reacts with some metals. This leads to arcing, which of course leads to fires.... Be _sure_ all your aluminumn connections are done with the special connectors & grease & so on. Don't just screw them in without checking this. Aluminumn requires special care on this.

--->Paul

I believe you are correct on the cable. The 2/0 is green jacketed for ground, then you have two black 4/0 conductors and another 4/0 black with white stripe-neutral. This is the current ground rod setup--inspected and approved: The ground rods are 8 ft copper and there are 2 placed 7 feet apart with 4 gauge bare copper connecting them back to one side of the neutral buss. Thats my question, how do both buss bars benefit from the seperate ground wire unless both are connected to it in the panel? Same question for the ground rod wire. This maybe an easy one for the electricians out there.

Problem with most products you buy today is they don't want to give you installation info for fear of liability or explain how it's designed to work, so the competion doesn't steal the tech easy. Sometimes that leaves us dirt farmers confused. Appreciate all the safety concerns.

You can remove the metal tie strap between the two "neutral" bars and install an insulating plastic strap, which Siemens sells. Next, bond ONE of the two bars to the cabinet with the green screw provided. Do NOT bond the other bar. Label the bonded bar with the "equipment ground" designator, and use this for your grounds. Connect the 2/0 green striped wire here, adding a lug if necessary. Use the other bar for the neutrals, connecting the white striped wire there.

The alternative method is to remove the green bonding screws and dedicate the two neutral bars exclusively as neutral bars. Buy one or two separate ground bars (a few dollars at Home Depot). Attach the ground bars to the cabinet using the 10-32 threaded holes conveniently provided by Siemens. This bonds the cabinet as well as physically securing the bars in place. The grounds go to the added ground bars and the neutrals go to the two original side bars.

Having done it both ways I prefer the second method, especially in this era of GFCI/AFCI breakers. It is easier to route the wires neatly if each cable does not have to be split to both sides of the cabinet, and there is always a neutral close to the hot for a GFCI breaker.

The Siemens ground bars are listed to allow TWO ground wires to be installed under each screw, provided they are 10AWG or smaller and the ground wires are twisted together. This can be helpful when you fill all 40 spaces in the panel and start to run out of places to put all the grounds. This is NOT generally accepted as a good practice for neutral wires, so don't do it there.

The Siemens panel has an extra lug included for 2/0 wire and is labeled to be used if required. It goes in place of the third screw on the left neutral bar, but they say nothing about removing the metal tie strap. They make it confusing. I like your # 2 idea and method for keeping wires neat.

Your experience that the ground and neutral connected together in "most" installations is because most installations combine the service disconnect means, the service overcurrent means, and the branch overcurrent protection devices all in one place ("the main panel"). The interconnect between the equipment grounding conductor and the neutral (aka the grounded circuit conductor) should happen ONLY at the service equpment and NOT at any other point fed from that building service drop, including sub-panels. This is also the point at which the grounding electrode is to be attached.

Connecting ground and neutral together is entirely INCORRECT for sub-panels, however. The ground and neutral should NOT be connected together anywhere else in the installation. The "helpful" display at many home improvement stores typically gets this wrong.

The rationale for keeping ground and neutral separate is to avoid "ground loops", and to avoid allowing neutral currents to take multiple paths back to the transformer. You can get many bad effects, including elevated voltage on metal boxes, current flow through the ground under buildings, etc. This has been known to lead to mysterious veterinary problems with livestock, as many animals are very sensitive to small leakage currents.

All subpanels should be fed with 4 wires. Ground and neutral should be kept separate beyond the service disconnect. There are exceptions in the electrical code which allow remote buildings to be fed with only a neutral (no separate ground) in some cases. Even if applicable, I would stronly recommend against this for a new installation.

Most people vastly overrate the effectiveness of the typical driven ground rod, and think that this is where return current or fault current travels. Having actually measured the resistance of several, I've found that even in moist soils it is difficult to get below 25 ohms on a typical driven 8 foot ground rod. These are primarily for lightning and surge protection, and do nothing in terms of useful distribution of electricity or providing a safe fault current path for short circuits.

"All subpanels should be fed with 4 wires. Ground and neutral should be kept separate beyond the service disconnect. There are exceptions in the electrical code which allow remote buildings to be fed with only a neutral (no separate ground) in some cases. Even if applicable, I would stronly recommend against this for a new installation."

The local code allows for the neutral only feed.

When Wiring the remote building with the seperate ground and seperate neutral as you suggest, should there be a ground rod driven and connected to the ground bus at the remote building? Or should it rely on the ground wire from the main panel only? It is an all metal building.

I have read about the ground rod being the imperfect but accepted way of grounding. Local code calls for 2 of them 7 feet apart.

Just got zoning this year and building codes within the last 5. So it's not the most knowledgeable inspection dept in the U.S. for sure!

No matter how you do it, the power company needs to know about the shop load. They need to size the transformer, connections from the transformer to the meter, and the service entrance conductors appropriate to the load to be served. This sizing is based on the actual expected load and not on the size of the main breaker in the panel or the sum of all the main breakers connected to the meter.

There are several safe and code accepted ways that you can connect multiple buildings to one meter. There are also lots of unsafe ways; some of those even appear to work, but are still unsafe.

A pedastal arrangement, or "yard pole" is one of the best ways to connect multiple buildings where the loads are significant in each building and perhaps unpredictable at this time. Here, you have a single set of conductors from the transformer secondary to the meter supply side, and then split out multiple conductors from the meter load side to the various buildings.

If the load in one of the remote buildings is relatively modest, you can install a sub-panel in building "B" and feed it from a circuit breaker installed in a main panel or sub-panel in building "A". The total calmculated load from both buildings must not exceed the capacity of the service entrance conductors/ feeder conductors going to the panel in building A. Done correctly, this is perfectly safe and code accepted.

One option you might consider is a "meter combo panel" attached to the outside of your future house, or to a pedastal/yard pole. Siemens makes one that will take up to 4 125 amp breakers, and also has a set of 200 amp feed-through lugs. Connect the 4/0 wires to the feed through lugs and run them to your shop. Wire your house as one or two sub-panels, with each sub-panel limited to 125 amps of total load, off the 125 amp breakers in the combo panel. You can use your already purchased "200 amp panels" as sub-panels fed from 125 amp breakers provided 125 amps is sufficient for the calculated load on that particular panel. Please be sure you understand the difference between a main panel and a sub-panel and handle the grounds and neutrals correctly.

If you are upsizing wire for voltage drop, and the wire won't fit the lugs, you can use a set of dual-rated Cu/ALR split bolts and a short length of smaller wire to make the connection to the breaker in question. Install some sort of enclosure to hold the splices (or make sure there is enough room in the main panel). Insulate the splices carefully. Just don't kid yourself that you have "200 amp service" to your shop if you are coming of a 100 or 125 amp breaker.

If your power company uses the pedestal system, they may install one for you. That is the only safe way to service more than one building off one meter.

You do not want to run service to your shop as a feeder circuit through another breaker panel. The shop needs a main disconnect directly off of the meter.

The cable does not have an "extra ground". It has a neutral and a ground. These must be tied together at the main disconnect and grounded to earth there as well. They must be separate at the breaker panel in the shop, although the ground should be grounded to earth at the shop. The breaker panel may have a jumper between neutral and ground; this must be removed.

You might want to check with your local electrical inspector so you don't have any surprises.