[Chazzmar]

Looking for input on a new residential build on 4 acre lot. The main electrical service comes in underground from the transformer to the front of the property at 1 phase 120/240. Here’s some details:
• The house build will be 160M away from the meter. (far distance)
• 150 Amp panel at the house.
• Planning to run paralleled 350 Kcmil AL conductors. To overcome 3% voltage drop.

Questions:

• I plan to install a splitter box below the meter socket to upgrade wiring to 350 kcmil for the lengthy cable run to the house. Can I ground the splitter box and house panel with separate dedicated ground rods at each end of the cable run to avoid running a bonding conductor between the splice box and the house panel? I don’t want to run an extra cable just to bond the panel and the splitter box together. Another thought, would the splitter box just have to be bonded to the meter socket? Isn’t the meter socket grounded to the system via the service neutral?

• Does 350 Kcmil paralleled seem to be the right size to overcome voltage drop?

Any thoughts are ideas are welcome. Thanks for the help

 

[mofos be cray]

You must run a bond. Why are you dicking around with a 150 A service? Put a 200 amp meter/main combo in and change the lugs to catch the 350. Or go meter to a fusible disconnect.
There are vd calculators, I suggest you find one you like.

 

[Chazzmar]

Thanks Mofos! Yeah it looks like they shook things up a bit since I really paid attention. Code used to allow seperate grounding rods on a single service.

I plan to have a 150Amp panel at the house to reduce the size of the supply cables required. 150 will be plenty for the required load.

In your experience would there be lugs available to catch 2 350s for each line? The 350s are run in parallel sets. I'm thinking a fusible disconnected might be the way to go.

The customer might also want power available at the service meter location as well so I might have to have a meter/panel combination which will then feed into a splitter box to upgrade to 350s for the run to the house... So many decisions. Thanks for your input

 

[Camproadninja]

350's in parallel seems like too much to overcome the 3% voltage drop.

One run of 350's sounds more likely to be correct for the voltage drop. It would probably be more cost effective to parallel 1/0 (I think, don't have my code book in front of me) then run 350.

 

[Chazzmar]

350's in parallel seems like too much to overcome the 3% voltage drop.

One run of 350's sounds more likely to be correct for the voltage drop. It would probably be more cost effective to parallel 1/0 (I think, don't have my code book in front of me) then run 350.

Thanks for the reply ninja, I used a voltage drop calc from Voltage Drop Calculator | Southwire website and was planning on using aluminum so the calulator spits out 2-350s for the required paralelled cable, is there a better calculator to use out there? It might however be easier for the install and more cost effective to use a parrallel set of copper 3/0 cables. Ill have to price them out.

 

[Chazzmar]

You must run a bond. Why are you dicking around with a 150 A service? Put a 200 amp meter/main combo in and change the lugs to catch the 350. Or go meter to a fusible disconnect.
There are vd calculators, I suggest you find one you like.

Just curious about the bond cable required. Will I need a seperate bond cable for each set of paralled cables? All the cables with be burried in the same trench so rule 10-602 might not apply to my situation...

Also a question the size of the bonding cable required. Rule 10-616 states the bond should be sized based on the largest ungrounded conductor. Does 10-616-4 apply because I plan to parallel the cables, or does it apply only if they're installed in seperate raceways... Im thinking of sizing a single bonding cable to Rule 10-616-3b, but I will size it to the ungrounded cable size before parallel cable calculations are applied... Thoughs?

 

[Bluenose for rent]

4/0 aluminium x2 in parallel or 400mcm aluminium
If you’re using cable the required bond is in already.
I would not be putting a splitter outside.

 

[Chazzmar]

4/0 aluminium x2 in parallel or 400mcm aluminium
If you’re using cable the required bond is in already.
I would not be putting a splitter outside.

Thanks Bluenose, just curious how you came up the the 4/0 aluminum x2? Do you use a voltage drop calculator online? The online calculator I've been using at Voltage Drop Calculator | Southwire keeps telling me I need 300 kcmils X 2 for a 160M run to a 150 Amp 240V service.

 

[Bluenose for rent]

Thanks Bluenose, just curious how you came up the the 4/0 aluminum x2? Do you use a voltage drop calculator online? The online calculator I've been using at Voltage Drop Calculator | Southwire keeps telling me I need 300 kcmils X 2 for a 160M run to a 150 Amp 240V service.

Thanks Bluenose, just curious how you came up the the 4/0 aluminum x2? Do you use a voltage drop calculator online? The online calculator I've been using at Voltage Drop Calculator | Southwire keeps telling me I need 300 kcmils X 2 for a 160M run to a 150 Amp 240V service.

I use a trade calculator app called Ecalc usually. Since I don’t have my tablet with me I googled it and used the next one down from the southwire one, which I couldn’t get to work.

 

[Bluenose for rent]

I use a trade calculator app called Ecalc usually. Since I don’t have my tablet with me I googled it and used the next one down from the southwire one, which I couldn’t get to work.

There is a formula in the code book in one of the appendixes which would be the safest way I think it’s in D

 

[mofos be cray]

I use ecalc but the book gives you better numbers. Everybody is right btw parallel 350s are way overkill for 150 amps at 160 meters. At the cost of that I'd put a couple transformers in.

 

[Chazzmar]

There is a formula in the code book in one of the appendixes which would be the safest way I think it’s in D

I guess another question a fella should be asking is what is the acceptable voltage drop %?

I use ecalc but the book gives you better numbers. Everybody is right btw parallel 350s are way overkill for 150 amps at 160 meters. At the cost of that I'd put a couple transformers in.

Thanks Mofos, im definetly not questioning anyones numbers, im just curious how they got them, trust but verify kinda thing. I've put the numbers though 5 different voltge drop calculators online and they all seem to suggest different cable sizes haha. You would think the calculation is black and white but there seems to be different varients that are considered on each calculator. I'll have a go with the code book calculation, afterall the smaller the cable I can get away with the better

Thanks again for the input

 

[SWDweller]

You do realize that all the codes are a minimum standard? The race to the bottom continues.

 

[Chazzmar]

You do realize that all the codes are a minimum standard? The race to the bottom continues.

Sure do, thanks for your help.

 

[mofos be cray]

I guess another question a fella should be asking is what is the acceptable voltage drop %?


Thanks Mofos, im definetly not questioning anyones numbers, im just curious how they got them, trust but verify kinda thing. I've put the numbers though 5 different voltge drop calculators online and they all seem to suggest different cable sizes haha. You would think the calculation is black and white but there seems to be different varients that are considered on each calculator. I'll have a go with the code book calculation, afterall the smaller the cable I can get away with the better

Thanks again for the input

Depends what math they're using. For example, I believe ecalc uses IEEE standards. Which is calculus based. The code uses simple algebra so it's not as easy to build in a whole bunch of fudge factor.

 

[eddy current]

I guess another question a fella should be asking is what is the acceptable voltage drop %?


Thanks Mofos, im definetly not questioning anyones numbers, im just curious how they got them, trust but verify kinda thing. I've put the numbers though 5 different voltge drop calculators online and they all seem to suggest different cable sizes haha. You would think the calculation is black and white but there seems to be different varients that are considered on each calculator. I'll have a go with the code book calculation, afterall the smaller the cable I can get away with the better

Thanks again for the input

You do realize that all the codes are a minimum standard? The race to the bottom continues.

What do you suggest? Installing larger wires than required?

 

[Chazzmar]

I use ecalc but the book gives you better numbers. Everybody is right btw parallel 350s are way overkill for 150 amps at 160 meters. At the cost of that I'd put a couple transformers in.

Sorry to keep bothering, just curious if you're talking copper or aluminum? If I do the calculation for copper it looks like parallel 3/0 is plently. However switching to aluminum i get parallel 300s. Also, what voltage drop are you shooting for? I've been using 2.5%. I dont think it specifies in the code book an exact drop on the service side however it states 3% max on branch and 5% total to point of utilization. So i thought 2.5% is a good compromise. I'm also using 120Amps as the load (80% of 150Amps as the code suggests)

Normally this would not be a huge deal, however when you lay 160M of cable at a fair price tag you want to make sure everything checks out.

Thanks again for your time with the conversation.

 

[eddy current]

@Chazzmar You need to keep the voltage drop from the point of utilization to the furthest outlet so it does not exceed 5%, and can not exceed 3% on any feeder or branch circuit.
You should wire the feeders to the panels so they do not exceed 2% loss so you have a full 3% of drop to play with on all the branch circuits.

 

[mofos be cray]

Sorry to keep bothering, just curious if you're talking copper or aluminum? If I do the calculation for copper it looks like parallel 3/0 is plently. However switching to aluminum i get parallel 300s. Also, what voltage drop are you shooting for? I've been using 2.5%. I dont think it specifies in the code book an exact drop on the service side however it states 3% max on branch and 5% total to point of utilization. So i thought 2.5% is a good compromise. I'm also using 120Amps as the load (80% of 150Amps as the code suggests)

Normally this would not be a huge deal, however when you lay 160M of cable at a fair price tag you want to make sure everything checks out.

Thanks again for your time with the conversation.

Also if you balance the circuit a majority of your load will effectively be 240v. Remember the neutral carries the unbalanced portion of the load. I personally would size it at 240v and then add a fudge factor for unbalanced load.

 

[Bluenose for rent]

I

Sorry to keep bothering, just curious if you're talking copper or aluminum? If I do the calculation for copper it looks like parallel 3/0 is plently. However switching to aluminum i get parallel 300s. Also, what voltage drop are you shooting for? I've been using 2.5%. I dont think it specifies in the code book an exact drop on the service side however it states 3% max on branch and 5% total to point of utilization. So i thought 2.5% is a good compromise. I'm also using 120Amps as the load (80% of 150Amps as the code suggests)

Normally this would not be a huge deal, however when you lay 160M of cable at a fair price tag you want to make sure everything checks out.

Thanks again for your time with the conversation.

I punched in 3% when I did it