I am told 10000W is the limit for a single phase meter. With 3 phase, it
can go higher. Since there are only two wires coming to the building, it
must be single phase. There is no point to install a 3 phase meter. Do
meters really limit the current? I think the real limiting factor is the
wires. The two incoming wires don't look terrible big. I'll measure them
In a sense they do -- if you try to push more current through *anything* than it's physically
capable of transmitting, it will act as a fuse. :-)
Well, yes, of course -- the point is that since your meter isn't rated for more than 10KW, the
wires supplying the meter probably aren't capable of carrying more than that.
That may not be your only problem, though: I bet the transformer isn't rated over 10KW
The meters don't really limit the curent. Usually the transformer that cuts
the high voltage down to the building voltage is what limits the current.
They usually have a fuse inside them that will limit the current, then the
wiring going to the building is sized for that ammount of load. The meter
is probably sized for a range of power as to where they are the most
accurate. A small building like yours may only need about 10 kw to operate
as a large company may need 1000 KW. A meter rated for the 1000 KW would be
on the low end for your building and may not be as accurate.
Probably what is really causing the voltage drop is the starting of the saw.
When a motor is first started it will draw lots more current (often several
to 10 times) than its running current. Fuses often have a small time delay
before they open depending on the ammount of overload. Say overload it by
5% and it may take 30 seconds, overload it by 25 % and you have 2 seconds,
and by 10 times the ammount, a tenth of a second as an example.
It looks like the size of the wiring possiably going to the building and
inside the building is not large enough to handle the high current loads.
I remember in my younger days the TV set would often do funny things every
time the refrigerator would start up.
My biggest takeaway from all the suggestions here is to get either
the saw or the scanner off the same circuit as the other. If there are
spare circuits in your breaker, have the saw moved to its own.
Simplistic I know, but that's how I think.
On Wednesday, January 28, 2015 at 9:52:47 AM UTC-5, rbowman wrote:
Did you see the next recent post, where he reported that the meter is
rated 10KW? Not exactly a hamster wheel, but it sounds like 40A.
Given that he says the 8A motor load drops it by 5V, the 100ft of
cheap extension cord, or cheap something, sounds possible.
On Wed, 28 Jan 2015 06:57:14 -0800 (PST), trader_4
It's become very obvious your service entrance is under rated. A 10KW
meter, probably the SE cables themselves. That second breaker panel was
probably added later on, and just hooked to the same meter and serv ent
You seemed a little shocked when I said 2000W is not much. Compared to
many machines in factories and other businesses, it's 'small'. A common
electric water heater or kitchen range in a home, are around the same
wattage, + or - a little. Farms have grain dryers that use that much or
significantly more power.
I'm wondering what the main breaker is in BOTH of your breaker boxes?
That i'm sure you can tell us, but then what is the gauge size of the
Service Entrance wires? And the overhead (or underground) cables that
go between the Pole Transformer and the SE Head?
If you dont want to upgrade and replace all that wiring, (since you
lease the place), maybe you can just have an electrician add a seperate
NEW Serv Entrance, right from the transformer to a dedicated breaker box
just for the saw. Or (I think you said there are 3 buildings), a new SE
to one building (the one with the saw preferably).
You really dont need an electrician to advise you (or bullshit you). Of
you can determine what gauge ALL the wires are, which feed your MAINS.
ALL of them between the transformer and your MAIN breaker, we can tell
you what kind of load you can handle. Then if you want to invest in one
of those clamp around AMP METERS, and measure the draw of your whole
business, (with and without the saw), we can tell you how much you're
* Clamp around AMP meters are simply clamped around wires at the MAINS.
They measure power draw by inductance. You dont really have to touch
any live wires. (of course you still need to do this safely, since
you're very near the bare connections). These meters are around $50 US.
At least they used to be, when I bought one around 20 years ago. Maybe
they're less now????
On 29/01/2015 04:14, email@example.com wrote:
I'll measure the wire gauge tomorrow.
The transformer is located in this building, the one we lease. Thus, it
would be easy to add another meter or replace the existing one and run
cables directly to the transformer, bypassing the cables that go to the
landlord's office. I did inquire about this option and was told it would
cost $600 to add a 3 phase meter. The 2.5 cm cables to the transformer
are the biggest cost. But then, I'm also told there can only be one set
of cables coming out of the transformer, meaning cannot add additional
cables to the transformer. (There are, of course, already existing
cables going to the landlord's office.) True or not, I don't know.
I cant tell you about your codes and number of wires to the transformer
since you're not in the US. You'll just have to speak with the
inspectors and a RELIABLE electrician. $600 does not sound like a bad
deal at all. If you have computers fail, or the motor on the saw fails
because of improper voltage, it may cost a lot more than $600.
If the meter is changed to 3phase, you can feed off each phase so there
may be no need to have more than one set of cables on the transformer
(per phase). Having 3 phase power is not something everyone has access
to. You should have adaquate power and much more.....
Plus, using 3 phase properly and balanced, could cut your electric bill
at least a little bit.
Otherwise, you can run some real heavy cables from the xformer to a MAIN
DISCONNECT box. Something like a 400 Amp main, they have sub feeds of
100A or higher, going to different buildings/ locations.
On 29/01/2015 05:55, firstname.lastname@example.org wrote:
OK. I checked the wires coming from the landlord's office. They are 0.7
mm thick, including the sheath. And they were lukewarm when I touched
them. I don't know if the warmth is due to the start-up current or the
constant 8.8 A (2000 W) draw.
On Thu, 29 Jan 2015 03:56:20 -0800 (PST), trader_4
Yea, that has to be 7mm. According to a little conversion program I
have, that would be .276 Inches (rounded). Or just slightly over 1/4".
Since he measured it WITH the insulation, that is not much of a wire in
gauge size. If I had a piece of #6 gauge wire around here, I'd guess
that would be close. #6 is nrmally used to wire a kitchen range, on a
50A breaker. Even a #4 is under 100A. Then too, is this cable copper
or aluminum. Alum S.E. cable needs to be quite a bit thicker.
I do not recall the OP ever posting the breaker size.
If the wires are warm, that alone indicates a problem with the system.
I am almost fully convinved that Service Entrance is way undersized.
That whole system is likely only capable of 60A from the main.
On Thursday, January 29, 2015 at 3:39:06 PM UTC-5, email@example.com wrote:
Well, he did say the meter was rated at 10KW. #6 is fine
for that ampacity.
Even a #4 is under 100A. Then too, is this cable copper
I don't either. I asked that today.
Probably only 40A, since that's what it appears the meter is rated for.
But even if it is rated for 40A, the question is what is he actually
pulling? Conductors shouldn't be getting warm and the voltage shouldn't
be dropping 5V from an increase in load of 8A. The latter is clear
indication that something is undersized.
On Thu, 29 Jan 2015 14:32:32 -0800 (PST), trader_4
A 40A main is nothing in today's standards. Here in the US, 60A was the
minimum allowed for a home, 50 years ago. Today, It's a 100A minimum,
or has the NEC increased that lately????
And the OP is running a business as well as a home on that 40A. It's no
wonder the wires are warm. That saw alone is using a large portion of
the avialable power. Then he has lights, a bunch of computers, and we
can only guess if there is an elec water heater, range, and who knows
I've asked the size of the main breaker several times.
Either way, it's apparent that this system is under rated and needs to
be replaced, or an additional Service entrance installed.
Appparently the codes are not as strict outside the US.
I'm on a farm, and I have a 400A main disconnect on the power pole,
which is feeding 100A main in my house, 100A main in my garage/shop,
100A main in my barn, and an outdated 60A fuse panel main in a very
small shed (which is mostly just used for a couple lights). I really
dont need that much power, but I'm glad it's over rated. I never see
On Thursday, January 29, 2015 at 8:13:58 PM UTC-5, firstname.lastname@example.org wrote:
It still doesn't affect the physics. If the total load is within that
limit, the conductors are properly sized, then turning on or off an 8A
load shouldn't cause a 5V voltage drop.
I know he talked about how it was wired up, but it wasn't clear
to me that the house was also served by the one meter, that it wasn't
a separate meter for the business, but you may be right. In which
case, I agree, it makes it worse. But curiously, if the service is
really that small and serves a house and business, there is no mention
of other problems, eg main breaker tripping. Maybe there are no
large loads, eg water heater, electric cooking, AC, etc. If all you
have are lights and some small appliances in a small house/business,
40A will go a lot farther.
On 30/01/2015 03:05, email@example.com wrote:
I studied the main panel and this is what I found. The incoming wires go
to the main breaker which is rated 32A (if my guess is correct). From
the breaker, the wires go to a switch. The switch is to switch between
power from grid and from generator. From the switch, wires go to two
The wires between the main breaker and the switch are two 4mm wires.
Instead of using one bigger wire, the person who set it up use two
smaller wires. (There is a total of 4 wires, two for hot, two for
neutral.) This 4mm is not diameter but cross section. So, actually, it
should be 4 mm2. These wires are warm and the switch is hot, estimated
I have a spare switch with larger capacity and 10 mm2 wires. I'll
replace the switch and wires first and see if the situation is improved.
32 A is s weird rating, but I'm only familair with U.S. equipment.
Either way, that is a really small Service. Heck, I have a 30A breaker
just on my elec water heater, and another on my clothes dryer.
No wonder you have so much voltage drop. You are way underrated, dn if
that stuff is getting warm and hot, you better do something soon, before
you end up with a fire. Even if it costs some money, I thik you should
replace the entire service entrance from the transformer to at least
those two sub panels, and maybe more. Your meter is too small, the
wires are too small, and the main breaker is too small. At least get a
100A main in there and upgrade all the wiring to match. And if
possible, get rid of those two sub panels and put it all in one box. A
breaker panel with a 100A main, and slots for at least 12 small breakers
are under $100 (U.S.). You'll probably have to replace the meter
socket. The power company supplies the meter. The rest of the cost is
the wire itself.
If you intend to add any other larger power tools, I'd suggest a 150A or
200A main. (Assuming those are rated the same. You might have 108A or
something???? Actually, I always thought breakers and fuses were rated
the same, worldwide. I guess not!
Regardless, you really need to upgrade even if it costs some money. A
fire will cost much more, and that saw motor wont last long running at
20 or 30 volts below its rating. The computers may lose power supplies
too, and who knows what else.
Unless you rewire everything, I think I'd run a dedicated separate cable
to that saw from your new main. It sounds like those wires are also too
small, because you have a considerable voltage drop at the saw, IN
ADDITION to the main dropping already.
Yea, that switch must be way too small to be getting that hot. You know
that you're paying money on your electric bill, just to make those wires
hot. That's a waste of $$$$.
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