ECN Forum Forums General Topics of the Trade General Discussion Area Voltage Drop

In New Zealand the supply characteristics as per AS/NZ3000:2000 are 1.8.2.
230/400 system ± 6%. 243.8V max. and 216.2 min.

under 1.8.4. I quote:
Unless an electrical installation is specifically designed to operate under reduced voltage conditions, the voltage drop between the point of supply and any point of the electrical installation shall not exceed 5% of the nominal voltage of the supply.

where Point of supply is: 1.4.71

The junction of the electricity distributor's conductors with the consumer mains.

Frequency value is not quoted here under 1.8.2. perhaps Mike can give the details here.
Under the 1987 regs appendix I. 1984. reg 14.
the frequency shall be maintained except for momentary fluctuations within ± 1.5% of the standard frequency e.g. 49.25 and 50.75 Hz. (for 50 Hz network.)

[This message has been edited by RODALCO (edited 01-20-2006).]

Radar & Gfretwell:

OK, I'm an Electrical Inspector, not Building. The State (NJ) mandates within the UCC that plans and specs submitted and approved for the permit be enforced. It's not a 'cowboy' thing.

Ie: Site lighting project; plans/specs require 3/4 x 10' grd rod at each pole base (29), #4 Cadwelded, 18" BFG.

Gfretwell....what's a "Suretest"????; NO I don't have one.

John

It was mentioned a few times in this post that a subpanel will provide voltage drop reduction.
Consider that a subpanel uses a relatively small feeder, and if there are a few loads on that subpanel, I would guess that voltage drop may be worse when the appliance can't draw directly from the service panel.

Radar inspection are handled differently in each area.

Where I am I have never had an inspector try to enforce the specs or prints.

At the same time the engineers know this and are either watching us directly or sending people out to watch us.

Personally I think this works well as they can come by anytime unexpectedly.

Bob

A Suretest is a handheld tester sold by Ideal that you usually see home inspectors using. Along with the usual ground/neutral checking it has a momentary voltage drop test using a 12a spike.

My concern with this type of thing as an inspector is you really need to know the load before you can compute voltage drop. I don't think it is reasonable to design every circuit for a 100% load at the farthest point.

2005 NEW MEXICO ELECTRICAL CODE States:
210.19 (A). General. Voltage drop. Add: “Conductors for branch circuits shall be sized to prevent excessive voltage drop. Conductors on 15 amp branch circuits, between the overcurrent protection device and the farthest outlet served, shall not exceed 75 feet for # 14 AWG copper circuit conductors, or 150 feet for # 12 AWG copper, measured along the branch circuit conductors. Conductors on 20 amp branch circuits, between the overcurrent protection device and the farthest outlet served, shall not exceed 75 feet for # 12 AWG copper, or 150 feet for # 10 AWG copper, measured along the branch circuit conductors. Branch circuits exceeding 150 feet from the overcurrent device to the farthest outlet served measured along the branch circuit conductors, shall be sized so that the voltage drop does not exceed 5%.”

The gov. must have lost a bet to the guy from COPPER.ORG

How are they enforcing this. Do they just guess how the wires are routed or do they bring a TDR? I suppose it is cheaper to just upsize +1 and hope they don't think you are over 150'.

HoseB:
Your State amendment sure sounds like what I see within specs doing plan review by some engineers.

As an AHJ, VD notes are checked on plan review; I/we do not 'measure' at field inspections. Basically, if #8 is on plans, that's what I/we look for.

John

I agree with Gfretwell....it looks to me like the AHJ has become facinated with the new testers out there.

You can be pretty sure the inspector isn't going to snake a tape measure along each wire to check its' length. Rather, he will simply plug in the latest 'whiz-bang' tester at what he thinks are the most remote receptacles, punch the "15 amp" button, and see what drop the meter reports.

Interesting as these meters are, I do not have one- simply because there are myriad other things calling for my money!

The meters are probably a good thing- I expect they will reveal more loss from bad connections than long wires- but making them a requirement is another thing altogether.

Why? If nothing else, is is not always clear just what a device tests for, nor are there always industry standard testing methods. The current debate over AFCI testers should caution everyone against blindly, enthusiastically accepting the latest marketing miracle.