Test for Audiophile-Ready House Wiring

One things audiophiles love to do is upgrade their home wiring, but honestly many do so with absolutely no justification.  They read about some Stereophile writer putting down $5k worth of new electrical work and an isolated sub panel with a ground field, yada yada yada, and they are immediately on the phone asking their electrician to run ten feet of cryogenically treated, but completely not NEC compliant battery cable for their amps. 

I am here to announce that there is finally a simple to use meter that will tell you if you need to upgrade your wiring, and if so how much better you could make it and it's about $20.  

Let me explain the magic here.  This meter continuously displays the N-E voltage which is difference between the Neutral and the Earth or ground.  With a little arithmetic we can use it as a proxy for how much voltage is sagging due to your wiring.  In other words, if we assume that the hot and neutral wires have about the same resistance then they should have the same amount of voltage drop across them.  Pretty cool, right?  

One outcome of this testing may be that you realize that most of the variation in your AC voltage is not because of your wiring but because of the normal power company variations in performance.  If that's true, a voltage regulator may be a much better solution for you. 

Preparing for Testing 

Before we get carried away lets make sure your house wiring is ready for this.  Turn off every bit of gear on the branch circuit which your audio gear is connected to.  Let's assume it is a dedicated circuit.  Leave the breaker ON.  Insert your brand new Kaiweets outlet tester. If any of the following are not true we already need to consider an electrician: 

- The two left red LEDs on top light up, but not the third

- The voltage is reasonably close to 120V. 

- The N-E voltage is 2V or less. 

The LED testing is something an experienced DIYer can often fix, but fixing the rest of this probably is going to require a conversation with your power company or a certified electrician.  Don't ask me for help, get a pro.

Assuming this testing is good, you are ready to begin evaluating your audiophile-grade AC circuit. 

 

As you might surmise, you can do this testing with a good multi-meter but this unit is damn convenient, and safe since you aren't sitting there with probes in your hands and outlets.  Still, if you have a good multimeter and comfortable probing your AC outlets go right ahead and use it, all the principles here will apply.   If you want to probe your AC outlets with a meter that's between you and your health insurance.

Testing

Note the L-N and N-E voltage before you turn anything on.  This is your baseline.  Note it does change over time and while the Kaiweets outlet tester is relatively accurate, it may fluctuate a little over time.  So if you see it say 0 or 1 V, call it 1. 

 

Next we are going to estimate how much sag your AC branch circuit has under load.  There's a couple of ways to do this, with music, or with a hair dryer.  The latter will give you the most consistent measurement, but it will probably overestimate your sag by a lot. 

 

Now, turn on all your audio devices, let them stabilize and warm up.  Now let's play some music! As loud as you can stand it. 

 

While it's playing (or while you have your hair dryer going) notice the voltage (L-N) go down and the N-E go up.  Generally speaking, the difference you see in the N-E voltage is half your voltage drop due to the wiring.  Lets go through an example. 

 

Baseline:  118V / 2V

Playing Music:  115V /4V

The difference in the N-E between baseline and music playing is 2V.  That's the voltage drop in the neutral.  Since both the hot and neutral have about the same voltage drop we estimate the total drop under load is 4V.  This means 4V is the absolute most you could get out of wiring upgrades.

But wait, how do I know this isn't the wiring from the utility company to my panel?  Good question! You can assess this the same way.  Put the Kwiweets on another, completely unused circuit. Bathroom counter outlets are usually great for this because by the NEC you can't put anything besides bathroom counter outlets on a circuit and each bathroom gets its own. Watch the N-E numbers there.  Pretty much anything you see here (with nothing else on) is measuring the whole house N-E sag.  If you see this going up and down significantly with say your AC or cooking or other appliances it's worth following up with an electrician.  They generally say that anything over 2V on the house neutral is cause for discussion.

The Physics of Remote Measurements

You might be wondering how any of this can work, or why it works.  It's worth talking a little more about.  Consider a branch circuit in a home.  Let's say it's very far away from the meter and main panel.  Assuming there is little to no current, then the voltage at the outlet is nearly identical to the voltage at the main panel. The reason is that voltage drop is proportional not just to the resistance on the way here, but to the current as well:

V = Amps * Ohms

is the basic equation, so assuming we have a mediocre circuit, or a very long 14 gauge circuit.  There's probably some resistance along the way.  Maybe 2 Ohms.  That's actually high, but let's assume it is. 

If you draw 0.010 amps with your test meter :

V = 0.010 * 2 = 0.020 V difference

So as long as you draw almost no current, your voltage measurement at any point in the circuit will be almost the same as at the meter.  This lets us "see" the neutral voltage for the entire house on any unused branch circuit.  

This also helps us "see" the neutral voltage because the ground wiring should never have any current inside the home, so no matter where you are when you measure N-E you should be measuring the voltage of the neutral relative to the ground rod outside.  Of course, sometimes this isn't true due to an appliance somewhere that leaks or has the Neutral and Earth bonded together but that's a whole other mess of problems.

Results

Audio gear has two kinds of power supplies today.  Linear, and switching.  Switching supplies are pretty immune to wide variations in AC voltages. 

 

Linear supplies in source components usually have regulators which maintain constant DC voltages even as the voltage sags to say 110V or less.  

 

Linear supplies in amplifiers however are almost all unregulated and therefore entirely at the mercy of the AC voltage for their status.  While they filter a great deal of noise, a long term 5% drop in the AC voltage results in a 5% drop in the DC voltages on the other side of that linear supply.  So if the amp's power supply normally has +- 50V, if the AC sags 5% it will only have 47.5V now.  If that sag is caused by music you now are in a situation where the music playing actually makes the amplifier weaker, and limits dynamic range. 

Ideally in these situations you should keep the voltage sag to about 3% or 4V or less to limit the amount of voltage drop which can affect your amps.   However many of us have this kind of variation occurring all the time due to power company fluctuations.  If that's you, you don't need better house wiring you need a voltage regulator, below.

Other Fixes

It is quite possible that you don't have a problem with your branch circuit but instead with the voltage at your home being very different at different times of the day but the utility company thinks it's OK.  In that case you need a voltage regulator.  

The Truth about Whole House Surge Suppressors

I've been reading a great deal of information/misinformation about Whole House Surge Protector (WHSP) and I wanted to make all of it more simple for the audiophile/videophile who may be on the fence about them.  

Should I get a WHSP? 

Yes.  Full stop.  No doubt about it.  The 2020 edition of the National Electric Code requires them for new construction the major justifications are the additional home automation devices (which need protection) as well as solar power panels, generators and battery backup/inverters (which cause surges)  becoming much more common.  Even before that though you probably have a lot of equipment in your home that is on 24/7 which would be expensive and time consuming to replace, such as: 

• HVAC units
• Refrigerators
• Stove
• Thermostats
• Smoke alarms
• Irrigation
• Outside lights and timers
• Wifi connected lights and outlets
  

 

A WHSP will help to protect all of them but you should still have a solid understanding of what exactly you should expect.  They are not full proof or perfect. 

Truthfully, protecting your home and electronics is a numbers game, and while homeowners who get whole house surge protection will do better than those who don't there are no guarantees that x event won't take out y device in your home.

Does a WHSP protect all of my devices?

Yes, but not equally.

All reputable WHSP makers make it clear that you should supplement their units with a good surge protector at the point of use, near the equipment to be protected.   

That's really all you need to know, but if you want to understand more, and why I make these claims, please read below.  

The Details

 

The online literature for WHSPs gets really dodgy, depending on who you are reading, either someone selling you a WHSP or a power strip, and you should get a nuanced story of what's really going on here. 

The WHSP job is to take punches for the team.  Every time there's a surge that makes it to your panel or meter the WHSP tries to take it but several factors prevent a WHSP from protecting everything at all times. Here's some of the limitations: 

• If a surge is too light ( < 600V) the WHSP may not even see it.  WHSP have higher let through voltages than a good surge strip.  Your electric range is going to be a lot less sensitive to this than your TV.
  
• If the surge is induced or starts inside the home but far from the panel the wiring itself may keep the voltage in the home several hundred volts higher than the panel ever sees.  So the WHSP may see 500V but your TV feels 1,000 V
• Almost all surge suppressors have an activation time. Lightning strikes are incredibly fast so at least some part of the leading edge is likely to get through.
  
• WHSP on your meter won't protect you from a surge coming in via the cable modem, TV antenna, etc.  
• Even if everything goes well a WHSP only softens the punch, it never 100% eliminates them.  As your equipment ages it gets closer and closer to failing with each of these light punches. 
• The quality of the wiring in your home matters, from the outlet all the way to the grounding electrode and power meter.  Even very small changes in impedance can alter how well surge protection devices can work.
  

 Another way to say this is:

The thing a WHSP does best is take on high voltage, high current surges from the power lines.  It also helps reduce the damage from internal surges caused by appliances turning off/on or induced by lightning. 

For all of these reasons most of us need a layered approach.  A WHSP in a panel or meter plus carefully selected surge protectors for our most expensive and delicate electronics.  I also strongly recommend an external coaxial surge protector if your home has any external antennas, CATV or Internet service that relies on coaxial cables.  See more below.

Installation Tips

•  Hire a registered electrician and have them inspect the ground electrode while they are there. 
• If you want to be a total geek, replace your ground electrode wire with "bare armored ground" all the way to your panel.  Because of skin effect and the high rise times of a lightning surge the BAG offers superior conductivity for lightning than bare copper.  During a lightning surge most of the current ends up in the metal sheath.  Make sure the sheath is grounded on both ends.  Yes, this is 100% code compliant. Yes your electrician will think you are a geek.
  
• If installing in your panel (and you should), install your WHSP as close as possible to the main panel breaker. 
  
• I've seen complaints about WHSP having leads that are too short.  There's a reason for this.  The longer the leads the less effective the surge suppressor can be.  Shorter is absolutely better here.
  
• Install for function, not looks.  Trim any leads as short as possible and avoid any sharp bends.  Think the radius of a soda can as the sharpest you should bend any leads or pigtail.  
• Attach as closely as you can to the incoming neutral and ground. 
• Line to neutral is more important than line to ground.  If you are installing the type with a pigtail make sure to attach it to neutral. The main reason is that the neutral cable is often much thicker than the ground in your panel, plus you avoid creating a shock hazard with a high voltage ground in your home.
• Distance matters.  If you have subpanels which are far from the main panel consider additional protection there.  This is why the 2020 NEC also requires surge protectors for attached buildings. 
• Always follow the NEC recommendations for grounding.  You may exceed them, but never create a second grounding scheme which is not bonded to the house grounding electrode.   

 

Protection from a sustained over-voltage

There is also one oddball condition that most surge strips and a WHSP won't even try to stop:  long lasting elevated voltages.  Imagine your 120V suddenly becomes 150 to 180V.  This can happen for instance with a bad neutral.  I've seen several manufacturers even put it in writing that they do not cover this condition at all.  In their mind a surge is an intense, short lasting high voltage situation.  These "over-voltages" are not surges and therefore not covered.

Some things with digital power supplies will function normally, like your PC, but any stereo equipment with a linear power supply can easily fry with long enough exposure.  Very few surge strips even see this problem happening.  For this I recommend Furman with SMP and EVS as the absolute best I know of.   

 

Coaxial Surge Protection

I strongly recommend the use of a gas discharge based coaxial surge protector to install on an external ground block.  Yes, the cable company will complain, but that's because most consumers end up using the surge protectors in cheap power strips which are often garbage for the signal.  This little gem is rock solid and because it is mounted outside your home will protect your wiring as well as internal electronics.  Use the same unit for external antennas.   I will repeat the idea though that no surge protector is perfect and that the possibility of a lightning strike inducing a damaging voltage remains no matter what you do.

 

The unit is extremely simple.  An outer grounded shell and an inner conductor.  Between them the little gas discharge tube sits and when the voltage exceeds a set amount (90V in this case) it conducts.  That's it.  The tube is reusable and replaceable. One of the most important reasons for having this unit is to prevent the coaxial cable itself from catching fire inside your home.  If you've seen pictures online of scorch marks following wiring inside the wall to a TV it's often because of a coaxial cable catching fire.  After installation I still get 500 MBPS download speeds and a strong modem signal both ways.

 

Will a WHSP protect me from internal and external power surges? 

Yes, but distance matters.  For instance, my meter is 20' from my main breaker panel. A WHSP at my meter won't shunt internal surges as well as a WHSP mounted on my panel.  The reason is the inductance in the wiring between my panel and my meter will increase the effective clamping voltage, and vice versa.  There's nothing wrong with having both.  

Can I rent WHSP? 

Depends on your power provider but a number now offer a service called Surgeguard (or something similar) where they will charge you a monthly fee for a WHSP they mount in the meter itself.  Still worth putting one into your electric panel, especially if it's not co-located with the meter.

 

What about the equipment warranty?

Read the fine print.  Most of it won't cover anything until after your insurance has, and won't cover your deductible.  

Lightning Frequency

One thing that may further motivate you to getting a WHSP is to look at the lightning frequency map.  This data is from Vaisala and used with permission.  The map covers 2015-2020.  This should give you a good idea of the risks you have from lightning strikes.  The more orange to red your county is the more likely you are to experience damaging lightning surges.

 

Surge Protector Specifications

I'm going to cover Siemens because that's what I have but most electrical panel makers have some version of what we are going to discuss. 

Breaker-less Surge Protection

Whole-house surge protectors come in a couple of flavors.  Those that require a breaker in front of them, and those which are breaker-less.  For Siemens this is the Boltshield line of products.  This is the one I use:

 

 

 

Super convenient, sounds an alarm when it's spent and you don't need extra breakers but they do take 2 slots. Now take a look at the specifications:

This particular Boltshield won't activate for any surge less than 600V.  Should excess current occur it will trip the main panel breaker, which prevents the unit itself from catching fire.  It is still worthwhile to protect all the devices in your home which don't have protection.  When the protection stops working it sounds an alarm to let you know it needs to be replaced. 

 

Square D also offers these types of surge protectors, such as the HomeLine which claims they clamps way down at 175V.

 

Bad news is that it doesn't have an alarm to tell you it's spent.  You have to keep checking that light.