Simple(?) wiring question.

[icor1031]

I am moving soon, but I will have a shed that I need to power, so I can use my wood work tools.

It's a rental, so I don't want to make permanent changes to the wiring.


The best power source I have access to is a 220v (USA, if it matters.) dryer outlet. It's on a 30amp breaker, and so far as I understand - the dryer outlets are also always rated for at least 30 amps.


Because I have 110v and 220v tools to power, this is what I want to do:

Run an 8/4 SOOW wire (as an extension cable, so as to not add any permanent wiring to the rental.) from that outlet, to my shed.

Split it 3 ways in the shed: I'll create two strings of 110v, by taking a single hot wire to each from the 220v. That will give me 60 amps (30 on each side) of 110v.

Last, I'll use both hot wires to create another 220v outlet for my 220v tool. That's 3 strings, and of course - when my 220v tool is running, I have fewer amps to give to the 110v lines.



Concerning outlets: My understanding is that I'm fine to use a 30 amp breaker on 15 amp outlets, so long as I don't draw more than 15 amps on that outlet.. The pass-through rating should be higher than 15 amps(?), but will it be enough for 30 amps?



Please be gentle, I'm a noob - and I know it :heart:.

I've heard conflicting answers whether it's okay to use both 110s on the 220. One person says the neutral wire will be running the sum (30+30 = 60, and therefore the neutral will get too hot.)..

Another person said that the neutral will only see the difference (if one 110v is @ 10amps, and the other is @ 5amps, the neutral sees 5 amps.)


What do you say, gentlemen?

 

[Octopus]

try a US based forum?

 

[telectrix]

you may get better advice from a USA member, Gnuusser. give him some time to see your post.

 

[icor1031]

I couldn't find any; the only one I saw is for electricians, not DIY people.

try a US based forum?

Thanks.

you may get better advice from a USA member, Gnuusser. give him some time to see your post.

 

[gnuuser]

you should set it up a portable sub panel. (also include gfci/rcd protection) and for a safety reason if you are planning on full load capability of the drier circuit then upgrade to 6 awg/4.11mm

if you intend to use just 8 awg/3.77mm then the maximum main breaker size you can have in the sub panel is 50 amp, and use the correct size breakers for the branch circuits
for example #14awg (copper) max current 20 amps (use a 15 amp breaker)
#12 awg (copper) max current 25 amp (use a 20 amp breaker)

((these are conservative max loads depending on the type if wire insulation so its a wise rule of thumb to follow))
this will prevent the wire from burning on you.

split phase circuits require balancing as well to prevent brownout conditions and unwanted harmonics in the stepdown transformers.

if you are unsure how to do this then please enlist the aid of a local electrician.
but be advised you need to check the regulations concerning sub panels in the area you are moving to

and the greatest part of it being a portable is if you move again you can take it with you

 

[icor1031]

Thanks, mate.

you should set it up a portable sub panel. (also include gfci/rcd protection) and for a safety reason if you are planning on full load capability of the drier circuit then upgrade to 6 awg/4.11mm

if you intend to use just 8 awg/3.77mm then the maximum main breaker size you can have in the sub panel is 50 amp, and use the correct size breakers for the branch circuits
for example #14awg (copper) max current 20 amps (use a 15 amp breaker)
#12 awg (copper) max current 25 amp (use a 20 amp breaker)

((these are conservative max loads depending on the type if wire insulation so its a wise rule of thumb to follow))
this will prevent the wire from burning on you.

split phase circuits require balancing as well to prevent brownout conditions and unwanted harmonics in the stepdown transformers.

if you are unsure how to do this then please enlist the aid of a local electrician.
but be advised you need to check the regulations concerning sub panels in the area you are moving to

and the greatest part of it being a portable is if you move again you can take it with you

 

[gnuuser]

your welcome
glad i could help

 

[Engineer54]

if you intend to use just 8 awg/3.77mm then the maximum main breaker size you can have in the sub panel is 50 amp,

Makes a bit of a mockery to the UK's Reg's does that!! lol!! I hope there isn't any electrical trainee's looking at installing showers or cookers points with 4mm cable and a 50A breaker!! lol!!

 

[gnuuser]

Makes a bit of a mockery to the UK's Reg's does that!! lol!! I hope there isn't any electrical trainee's looking at installing showers or cookers points with 4mm cable and a 50A breaker!! lol!!

if you read the original post carefully the op is desiring a service to a wood shop
and he is in the USA.
there is little chance hes installing a cooker or shower in a wood shop!
the info (ampacity tables) we have are based on industrial and commercial conductors. more often than not there is a lot of difference between those and residential type cabling due to insulation type and sheathing

after a bit of careful searching heres a pdf concerning romex, uf and residentiol style conductors and the ampacity.

http://sparkyjohn.com/ampacity/ampacity.pdf


i do not have the luxury of having a set of the UK. regs and it would be foolish of me to purchase a set just for the purpose discussing things on the forum.

that said and done I appreciate your info and opinions on the different requirements.and I value it as well.
but please have the same courtesy with me
It is by comparing the differences and using that info to learn and improve our own is what makes forums important.
we are professionals here fellows respect each other for that

 

[Engineer54]

if you read the original post carefully the op is desiring a service to a wood shop
and he is in the USA.
there is little chance hes installing a cooker or shower in a wood shop!
the info (ampacity tables) we have are based on industrial and commercial conductors. more often than not there is a lot of difference between those and residential type cabling due to insulation type and sheathing

after a bit of careful searching heres a pdf concerning romex, uf and residentiol style conductors and the ampacity.

http://sparkyjohn.com/ampacity/ampacity.pdf


i do not have the luxury of having a set of the UK. regs and it would be foolish of me to purchase a set just for the purpose discussing things on the forum.

that said and done I appreciate your info and opinions on the different requirements.and I value it as well.
but please have the same courtesy with me
It is by comparing the differences and using that info to learn and improve our own is what makes forums important.
we are professionals here fellows respect each other for that

I wasn't having a pop at you gannuser, just pointing out the difference between Your codes and the UK regs. Unlike the States, the UK have a diabolical training system that allows guy's to go from stacking shelves at a supermarket to being allowed to go into peoples homes undertaking electrical installation work in 5 WEEKS (5 week wonders as they are called/known by the real qualified sparks). My comments on cookers and shower units were relating to them, not you or the OP's post.

There is to my knowledge, no cable used in UK domestic wiring installations where a 4mm cable can carry 50A or be protected by a 50A OCPD , unless it's been wired in MICC, which is quite rare to see these day's and a electrical trainee wouldn't know what to do with that cable anyway!! lol!!

 

[gnuuser]

good lord! i know what you mean about Electrical Trainee. we have some of them who get put in charge of equipment they have no understanding about (I thing someones trying to let the darwin equation take care of them)
IMHO.a lot of the problems abound because there are no complete international references and guidelines for either of us to follow.
and sometimes the info we get may not be that accurate
more often than not I usually research as many references i can to compare the info
and its by us professional guys and gals in the field communicating with each other that help us all to better understand.

 

[overskilled]

Methinks wires are crossed here a tad.....
Wire Gauge Tables

6awg is 13mm2 CSA
8awg is equiv to 8mm2 CSA

Gnu: I have a copy of the Big Red Book (BS7671:2008 - 17th edition - the Big Green Book is an amended version of it) going spare if you want it posted out to you for a look at?
Its broadly similar to the BGB and would give you an insight into the differences between BS7671 and the NEC.
Interested?
Wouldn't mind having a nose at the NEC myself to see the differences...

 

[gnuuser]

it could be
Ive been working a lot of double shifts to get caught up
and probably read the scales wrong
now they want me to attend some classes also
I guess I just have to pull the extra time out of my arse somehow

 

[overskilled]

Could be 4mm circumference compared with 8mm cross sectional area

 

[gnuuser]

the conversion app on my phone is incorrect (confusing as crap)
that ones gonna get uninstalled quick
I checked three different converion charts to verify it.
anyway heres one of the correct charts
AWG to square mm Wire Gauge Conversion