Electrical Engineering

Author

wire guage

dummy

2006-02-28, 7:21 pm

If I run a 10 guage wire from the breaker that is hot do I need a 10
guage neutral wire if I fully load the circuit?

Ryan Evans

2006-02-28, 8:21 pm

"dummy" <ghegg@hotmail.com> wrote in message
news:1141165346.037232.176180@i39g2000cwa.googlegroups.com...
> If I run a 10 guage wire from the breaker that is hot do I need a 10
> guage neutral wire if I fully load the circuit?
>

Yes.

SQLit

2006-02-28, 11:21 pm

Bill Kaszeta / Photovoltaic Resources

2006-03-01, 12:21 am

On 28 Feb 2006 14:22:26 -0800, "dummy" <ghegg@hotmail.com> wrote:

>If I run a 10 guage wire from the breaker that is hot do I need a 10
>guage neutral wire if I fully load the circuit?
>
Depends on the breaker rating, type of insulation, configuration (open air, conduit,, etc.).
In the USA see the tables in Article 310 of the National Electrical Code. #10 can be
used with circuit breakers rated for 30A (60C wire) to 40A (90C wire). Neutral and
ungrounded need to be at least the size/type indicated for the circuit breaker
rating. Also, do not install recepticles, etc. rated for 15A on a circuit protected with
a circuit breaker of higher rating.
Bill Kaszeta
Photovoltaic Resources Int'l
Tempe Arizona USA
bill@pvri-removethis.biz

Rich256

2006-03-01, 12:21 am

dummy wrote:
> If I run a 10 guage wire from the breaker that is hot do I need a 10
> guage neutral wire if I fully load the circuit?
>

Sure, It carries the same current as the hot.

Ben Miller

2006-03-01, 12:21 am

"Bill Kaszeta / Photovoltaic Resources" <kaszetaw@mindspring.com> wrote in
message news:44051355.22852608@news.east.earthlink.net...
> rating. Also, do not install recepticles, etc. rated for 15A on a
> circuit protected with
> a circuit breaker of higher rating.

It is ok to put 15A receptacles on a 20A circuit. Perfectly safe, and meets
code.

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

dummy

2006-03-01, 12:21 am

Thanks for all the great information...it actually made me think of
another question. Is it possible to put 27 (100W or lower bulbs)
lights on this 30A breaker or would it be safer to split it into 2 or 3
seperate 15A breakers. I wonder this because of the comment about
putting 15A receptacles on this breaker?

electrician@electrician.com

2006-03-01, 2:21 am

<Depends on the breaker rating, type of insulation, configuration (open
air, conduit,, etc.).
In the USA see the tables in Article 310 of the National Electrical
Code. #10 can be
used with circuit breakers rated for 30A (60C wire) to 40A (90C wire).
Neutral and
ungrounded need to be at least the size/type indicated for the circuit
breaker
rating. Also, do not install recepticles, etc. rated for 15A on a
circuit protected with
a circuit breaker of higher rating. >

The above statement does not apper correct.
Other than for motors, motor-compressors, and maybe some other uncommon
circuits AWG No. 10 copper cannot be installed on a 40 ampere breaker
per 240.4(D). The No. 10 with a 90 degree C insulation can be used
where derating is done with the 90 degree C. ampacity but the conductor
can not be used on a breaker greater than the 30 amperes. Also, AWG
No. 10 aluminum is limited to a 25 ampere breaker per 240.4(D).

(Try my Table 310.16 calculator at http://www.electrician.com it just
took 10 weeks to get it right.)

A 15 or 20 ampere rated multi receptacle that includes the common
duplex can be installed on a 15 or 20 ampere rated circuit per Table
210.24. However, a single individual receptacle on an individual
branch circuit must be rated at least the same as the circuit per
210.21(B)(1).

electrician@electrician.com

2006-03-01, 2:21 am

I stand to be corrected. A 20 ampere receptacle cannot be installed on
a 15 ampere circuit per Table 210.21(B)(3). A 15 ampere maximum
receptacle is all that is allowed. I don't recall this being in some
earlier editions of the Code. However, a 15 or 20 ampere receptacle
can be installed on a 20 ampere branch circuit other than an indiviual
branch circuit.

Bud--

2006-03-01, 3:21 am

dummy wrote:
> Thanks for all the great information...it actually made me think of
> another question. Is it possible to put 27 (100W or lower bulbs)
> lights on this 30A breaker or would it be safer to split it into 2 or 3
> seperate 15A breakers. I wonder this because of the comment about
> putting 15A receptacles on this breaker?
>

The NEC doesn't permit lights on 30A ckts for residential. For
non-residential "fixed lighting units with heavy duty lampholders" can
be on 30A ckts. For residential you need 2 15 or 20A ckts. Likely a good
idea in non-residential too.

bud--

Salmon Egg

2006-03-01, 3:21 am

On 2/28/06 2:22 PM, in article
1141165346.037232.176180@i39g2000cwa.googlegroups.com, "dummy"
<ghegg@hotmail.com> wrote:

> If I run a 10 guage wire from the breaker that is hot do I need a 10
> guage neutral wire if I fully load the circuit?
>
Yes.

-- Ferme le Bush

Salmon Egg

2006-03-01, 3:21 am

On 2/28/06 8:08 PM, in article
1141186085.549438.302230@j33g2000cwa.googlegroups.com, "dummy"
<ghegg@hotmail.com> wrote:

> Thanks for all the great information...it actually made me think of
> another question. Is it possible to put 27 (100W or lower bulbs)
> lights on this 30A breaker or would it be safer to split it into 2 or 3
> seperate 15A breakers. I wonder this because of the comment about
> putting 15A receptacles on this breaker?
>

That should not be a problem except that the inrush current may be many
times 30A. I can conceive of situations where that might trip a breaker or
not allow full voltage to develop.

-- Ferme le Bush

Bud--

2006-03-01, 3:21 am

electrician@electrician.com wrote:

> I stand to be corrected. A 20 ampere receptacle cannot be installed on
> a 15 ampere circuit per Table 210.21(B)(3). A 15 ampere maximum
> receptacle is all that is allowed. I don't recall this being in some
> earlier editions of the Code. However, a 15 or 20 ampere receptacle
> can be installed on a 20 ampere branch circuit other than an indiviual
> branch circuit.
>

I believe it is a long term requirement. It doesn't make sense to allow
a 20A device on a 15A circuit.

But from your first post, if you have only one outlet on a 15A circuit
it can be 20A, or 30A, 100A.... A strange rule.

bud--

Ben Miller

2006-03-01, 11:21 am

"Bud--" <remove.BudNews@isp.com> wrote in message
news:f3f7f$440543c8$4213ea2e$4751@DIALUPUSA.NET...
> But from your first post, if you have only one outlet on a 15A circuit it
> can be 20A, or 30A, 100A.... A strange rule.
>

NEC table 210.24 spells this all out...

15A receptacle on 15A circuit
15 or 20 A receptacle on 20A circuit
30A receptacle on 30A circuit
40A receptacle on 40A circuit
50A receptacle on 50A circuit

The circuit rating ids the OCPD rating. You can't put the smaller devices on
the higher rated circuits, as the utilization equipment and cords would not
be protected adequately by the OCPD. You can't put the larger devices on the
lower rated circuits, because that would obviously allow equipment to
overload the circuit and trip the OCPD.

For lighting, only 15 or 20 A circuits are allowed in a residence. You can
go higher in non-residential applications with heavy duty lampholders.

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

Ben Miller

2006-03-01, 11:21 am

One correction... you can use 40A or 50A receptacles on a 40A circuit.

Ben Miller
--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com
"Ben Miller" <benmiller@worldnet.att.net> wrote in message
news:t-Gdncd_3cV1LpjZRVn-sQ@comcast.com...
> "Bud--" <remove.BudNews@isp.com> wrote in message
> news:f3f7f$440543c8$4213ea2e$4751@DIALUPUSA.NET...
>
> NEC table 210.24 spells this all out...
>
> 15A receptacle on 15A circuit
> 15 or 20 A receptacle on 20A circuit
> 30A receptacle on 30A circuit
> 40A receptacle on 40A circuit
> 50A receptacle on 50A circuit
>
> The circuit rating ids the OCPD rating. You can't put the smaller devices
> on the higher rated circuits, as the utilization equipment and cords would
> not be protected adequately by the OCPD. You can't put the larger devices
> on the lower rated circuits, because that would obviously allow equipment
> to overload the circuit and trip the OCPD.
>
> For lighting, only 15 or 20 A circuits are allowed in a residence. You can
> go higher in non-residential applications with heavy duty lampholders.
>
>
> Ben Miller
>
> --
> Benjamin D. Miller, PE
> B. MILLER ENGINEERING
> www.bmillerengineering.com
>

Bud--

2006-03-01, 1:21 pm

Ben Miller wrote:
> "Bud--" <remove.BudNews@isp.com> wrote in message
> news:f3f7f$440543c8$4213ea2e$4751@DIALUPUSA.NET...
>
>
>
> NEC table 210.24 spells this all out...
>
> 15A receptacle on 15A circuit
> 15 or 20 A receptacle on 20A circuit
> 30A receptacle on 30A circuit
> 40A receptacle on 40A circuit
> 50A receptacle on 50A circuit
>
> The circuit rating ids the OCPD rating. You can't put the smaller devices on
> the higher rated circuits, as the utilization equipment and cords would not
> be protected adequately by the OCPD. You can't put the larger devices on the
> lower rated circuits, because that would obviously allow equipment to
> overload the circuit and trip the OCPD.
>
> Ben Miller
>

Entirely reasonable. But 210.24 applies to 2 or more receptacles on a
circuit as does 210.21-B-3. Single receptacles on a circuit are covered
by 210.21-B-1: "rating not less than the branch circuit". About 1/2
year ago someone figured out that section allows a 100A receptacle on a
15A circuit - "a strange rule". (Not that anyone with any brains would
do that.)

bud--

Ben Miller

2006-03-01, 2:21 pm

"Bud--" <remove.BudNews@isp.com> wrote in message
news:3684a$4405d528$4213ebb1$9078@DIALUPUSA.NET...
> Entirely reasonable. But 210.24 applies to 2 or more receptacles on a
> circuit as does 210.21-B-3. Single receptacles on a circuit are covered
> by 210.21-B-1: "rating not less than the branch circuit". About 1/2 year
> ago someone figured out that section allows a 100A receptacle on a 15A
> circuit - "a strange rule". (Not that anyone with any brains would do
> that.)
>
> bud--

Yes indeed. Even the handbook explains it as "For example, a single
receptacle on a 20-ampere circuit must be rated at 20 amperes;...".
Hopefully common sense prevails in some cases!

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

daestrom

2006-03-01, 7:21 pm

"Bill Kaszeta / Photovoltaic Resources" <kaszetaw@mindspring.com> wrote in
message news:44051355.22852608@news.east.earthlink.net...
> On 28 Feb 2006 14:22:26 -0800, "dummy" <ghegg@hotmail.com> wrote:
>
> Depends on the breaker rating, type of insulation, configuration (open
> air, conduit,, etc.).
> In the USA see the tables in Article 310 of the National Electrical Code.
> #10 can be
> used with circuit breakers rated for 30A (60C wire) to 40A (90C wire).
> Neutral and
> ungrounded need to be at least the size/type indicated for the circuit
> breaker
> rating. Also, do not install recepticles, etc. rated for 15A on a
> circuit protected with
> a circuit breaker of higher rating.

I agree with everything except that last statement. If the circuit is
dedicated for one outlet (such as refrigerator or disposal or some such),
then yes the receptacle must also be rated for the same current as the
breaker. But if there are several receptacles such as a typical branch
circuit, it is acceptable to put 15A receptacles on a 20A circuit. The NEC
allows this as it assumes you can't plug an appliance rated for more than
15A into a 15A receptacle (you can't because the plug design would be
different), and the circuit could have several loads that are < 15A that add
up to > 15A.

daestrom

dsky

2006-03-05, 4:21 am

Gentlemen, "if I were the owner of the establishment or house, I want
the 30 A rated receptacle( if there is any available ) for my 20 A ckt,
the price will not be significant for a single house (for many houses
like a condominium, the difference is substantial, a differnt case )
for the reason that it is much durable ( not easily heated by a
temporary excess current ) than a lower rated 20 A, it is my right to
load my property as I see fit, that is why I paid for a 20 A circuit
brkr that is suppose to trip if it a sustained over 20A current passes
to it. I will not accept the NEC limiting me on this."

For the case of a big savings when using a a smaller receptacle rating,
"I will put a 10A or 15A receptacles on a 20 A circuit for the reason
that high load appliances are seldom used and that there are many
receptacles to plug on,the chance of over loading an outlet is remote,
also a failure of a receptacle in case of overload (i.e short
circuiting the wires bcoz of melting of insulating barrier at terminals
or near the wires) will again trip the breaker due to instantaneous
overcurrent there by stoping further burning.. Again that is why a "cb"
is used, whats the purpose of thousnds of men,countles hours spent in
developing this thing. Again there is another "Main cb" that will I had
to buy."( this idea is dangerous if not consistent with the fire rating
of the house materials used. As insurance will not cover accidents
caused by violaton of the Code. As practioners we must not conceed the
compliance of the with our clients " economic philosopy " as fires are
caused by a violent spark on (gas)LPG leaked locations or near
combustible materials like curtains.)

>From my experience most device failures happens from heating caused by
high contact resistance when a loose connection occurs between plug &
receptacle,( I suggest UL listed and genuine products should be used, &
stop using those cheap asian things) which the responsibilty of the
user, I think that education has a role here.

Also if can be supplied by a utility company,apply for a 220 or 230
line to neutral service for branch circuits , or for three phase 400 /
230v for service of large occupancies. This is to take advantage of the
600v ratings of the wires, & majority of the materials used.

dsky

2006-03-05, 4:21 am

Ben Miller

2006-03-05, 8:21 pm

"dsky" <dsky_max@yahoo.com> wrote in message
news:1141544777.091299.284330@u72g2000cwu.googlegroups.com...

From your reference to the NEC I will assume you are talking about the US.

> Gentlemen, "if I were the owner of the establishment or house, I want
> the 30 A rated receptacle( if there is any available ) for my 20 A ckt,
> the price will not be significant for a single house (for many houses
>

You won't be able to plug in any appliances or equipment with 15 or 20A
plugs on them.
They are a different configuration than the 30A receptacles.

> For the case of a big savings when using a a smaller receptacle rating,
> "I will put a 10A or 15A receptacles on a 20 A circuit for the reason
> that high load appliances are seldom used and that there are many
> receptacles to plug on,the chance of over loading an outlet is remote,
> also a failure of a receptacle in case of overload (i.e short
> circuiting the wires bcoz of melting of insulating barrier at terminals
> or near the wires) will again trip the breaker due to instantaneous
> overcurrent there by stoping further burning.

There are no 10A. You can use a 15A on the 20A circuit. Understand that the
15 & 20A devices are actually the same, except for the "T" slot on the 20.
There is no advantage or disadvantage from a reliability standpoint to using
either rating on a 20A circuit, as long as you don't need the right-angle
slot.

> high contact resistance when a loose connection occurs between plug &
> receptacle,( I suggest UL listed and genuine products should be used, &
> stop using those cheap asian things) which the responsibilty of the
> user, I think that education has a role here.
>

That is sometimes a factor. However, loose terminal screws also play a part,
as does insulation deterioration or manufacturing defects.

>
> Also if can be supplied by a utility company,apply for a 220 or 230
> line to neutral service for branch circuits , or for three phase 400 /
> 230v for service of large occupancies. This is to take advantage of the
> 600v ratings of the wires, & majority of the materials used.

Have you looked at the voltage rating on building wire? It is 600 volt.
Aren't you better off with the lowest system voltage, which gives the
greatest margin of safety, if that is your concern?

As for the service ratings, you can't get 230 to ground. You can get 240
volt three-phase if you want it. However, I wouldn't recommend it unless you
need it. The higher available fault current that you will likely get
requires more expensive panels, and could present more of a hazard than
whatever you are concerned about. Also, how are you proposing to operate all
of the 120 volt appliances?

Ben miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

dsky

2006-03-07, 9:21 am

oh I forgot, the receptacles I was refering to was from the same asian
products,there are 10A 30A but not the nema config. these are
universal type blade & pin type plugs can go in. has 250V rating. Any
chance I can use it here in the USA.

Also do you know that insulating stregnth of thermoseting plastics are
the same for 220 and 440v up to 600v, they behave the same within that
voltage range. the only detriment will be the temperature to which they
might be subjected to or build up. Safety & capacity(i.e. lower 1st
cost ) Its the amount of power that can be transmitted to the wire,
especially for large residentials such as high rise condominiums, long
multistory apartments which the advantage can taken.Safety is the same
whether 220 or 440 v is on a 600v wire.

Also why is 400LL/230LN vac service not available , in europe this is
available, is it due to the cost of maintning an invetory of different
transformers ratings that most utility company objects?

Appliances today are autovolt types 110/220, lamps of 220v are already
common. If only 230 v utilization voltage was used, will the Inspector
approve it?

Also fault current is lower at 400v or 480v than on 240v, basing on cb
catalogs and by point method calculation.

Ben Miller

2006-03-09, 11:21 pm

"dsky" <dsky_max@yahoo.com> wrote in message
news:1141734008.590969.209440@j33g2000cwa.googlegroups.com...
> oh I forgot, the receptacles I was refering to was from the same asian
> products,there are 10A 30A but not the nema config. these are
> universal type blade & pin type plugs can go in. has 250V rating. Any
> chance I can use it here in the USA.

Not if they don't have agency approval, from UL or equal. But regrdless, why
would you want to if NEMA plugs won't fit them?

> Also do you know that insulating stregnth of thermoseting plastics are
> the same for 220 and 440v up to 600v, they behave the same within that
> voltage range. the only detriment will be the temperature to which they
> might be subjected to or build up. Safety & capacity(i.e. lower 1st
> cost ) Its the amount of power that can be transmitted to the wire,
> especially for large residentials such as high rise condominiums, long
> multistory apartments which the advantage can taken.Safety is the same
> whether 220 or 440 v is on a 600v wire.

I am not sure what your point is here. I said that 600V wiring is used
regardless of the system voltage. It would be safe at 440 volt.

> Also why is 400LL/230LN vac service not available , in europe this is
> available, is it due to the cost of maintning an invetory of different
> transformers ratings that most utility company objects?

US voltages are all based on 120V L-N. The standard voltages are all
multiples of 120 or 1.73 times 120.
This is how the US does it. Other countries are different. To see our
standard low voltage systems, visit
http://www.bmillerengineering.com/elecsys.htm

> Appliances today are autovolt types 110/220, lamps of 220v are already
> common. If only 230 v utilization voltage was used, will the Inspector
> approve it?

220V lamps are not common in the US. 120 or 240/120 volts are the standard
residential voltages. The NEC restricts the voltage for lighting and
cord-connected units under1440 VA in a dwelling unit to 120 volts, so an
inspector will not approve a straight 240 volt system.

> Also fault current is lower at 400v or 480v than on 240v, basing on cb
> catalogs and by point method calculation.
>

True, if all else is equal. My point was that when a utility runs a
three-phase supply to your house, they very likely will use larger lines and
a larger transformer than just what your needs are. As a result, even at the
higher voltage you may get higher available fault current. You would be
going to industrial boxes and breakers, which are more expensive. And, you
still didn't say how you plan on powering all of the 120 volt single-phase
loads. What is the point of all of this?

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

dsky

2006-03-11, 9:21 am

Dear Ben
Sorry to get u into this trouble, a year ago my american friend ask me
about the electrical system of a 30 story condo.His business partners
are planning to put it near a beach in Thailand.Since I worked there
for quite sometime, they ask me for my recommendation.
1.The Utility practice there is that all energy meter is at ground
floor,(otherwise its a private meter if located per floor and utility
will have main meter at transformer secondary, building admin will bill
the occupants)
2. All service above 500KVA, Client will have to give 60% deposit for
service transformers to be deducted on billings for 10 years. Secondary
Voltage is per client request.
My recommendation to him is the following.
3. Use utility metering so that Building admin will not bother itself
with billing the occupants.This mean that each Unit feeder will run
down to the Utility meter room.
a. I suggest to use the 400V 3PH 4W distribtion voltage, with 230V
L-N as utilization voltage, central split-AC for each units can use the
400V 3ph.
this will give maximum savings on materials such as feeder
wires,( higher load capacity for same size of wire, lower power loss
due to voltage drop. this is the point that I'm stressing on our
previous correspondence on using 400V for a 600V wire instead of 230V,
as we agreed both are safe.) and smaller breaker ratings,
b. All lightings and appliances are on 230V, this is the normal
voltage here, and I think on other asian countries as such as Japan,
Singapore. and that no shock fatalities have been of significant
occurences on these countries using this voltage.
c. With a single voltage, Universal type ( can accept pin or blade
plugs) receptacles can be used, all nema types except locking can be
used.
d. The percent impedance for a distribution type Padmouted
Transformer (used by Utility ) is the same for 400 or 230V secondary at
same KVA. So the fault duty is smaller for 400V dist.voltage. Also
cascade ratings can be applied for branch CB's since this is mostly
lighting & receptacle loads. Industrial type CB's are not necessary.
e. For wiring method I suggested the used of Cu-XLPE-PVC multicore
cable (also common here ) feeder run on vertical cable trays.Generally
they are also using the NEC but as a guide only.
If things push through I may be the have to design the plan for this,
they are already processing the acquisition of the property. Thanks for
pointing out that this will not be approved here in the US, However if
I use a dry type transformer at 120V for each unit (for lighting & 1
duplex outlet per area) will it be approved?
Thanks for your generous replies, Mr Ben , I really appreciate and
truly treasure the insights you gave.
Good Luck and may you prosper more on your business.

Dsky
Electrical Supervisor

Ben Miller

2006-03-11, 10:21 am

"dsky" <dsky_max@yahoo.com> wrote in message
news:1142082330.810532.143050@z34g2000cwc.googlegroups.com...
> If things push through I may be the have to design the plan for this,
> they are already processing the acquisition of the property. Thanks for
> pointing out that this will not be approved here in the US, However if
> I use a dry type transformer at 120V for each unit (for lighting & 1
> duplex outlet per area) will it be approved?

There is nothing wrong with using a transformer, but you will need more than
one duplex receptacle. The NEC requires a number of them within a dwelling
unit (Kitchen counters, bathrooms, along walls, etc.). You really need to
study up on the national and local codes that will affect your project, or
else hire a local consultant to assist you.

Good luck

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

dsky

2006-03-11, 11:21 am

Dear Ben,
if however, it were not in the US and with no 120V xfmr, are the rest
of my recommendations agreable to you personally? My friend is cutting
cost on consultants and will hire a PE only to sign the plans after I
prepared them. Thanks again.
dsky

Ben Miller

2006-03-11, 5:21 pm

"dsky" <dsky_max@yahoo.com> wrote in message
news:1142087373.482055.266980@v46g2000cwv.googlegroups.com...
> Dear Ben,
> if however, it were not in the US and with no 120V xfmr, are the rest
> of my recommendations agreable to you personally? My friend is cutting
> cost on consultants and will hire a PE only to sign the plans after I
> prepared them. Thanks again.
> dsky
>

I can't really comment without seeing the plans.

Tell your friend he will get what he pays for. No legitimate PE will sign
your plans, as it violates the law. PEs can only sign plans prepared by them
or under their direct supervision.

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

dsky

2006-03-18, 7:21 am

Most PE's I know liked it better that way, but must let them have it
their way. Usually no big problem.
If things went ok, I'll show it.
Thanks again, Ben

Dsky

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