How to isolate RJ11?

[sam1275tom]

Hello everyone, I'm using ADSL and the incoming line is RJ11 telephone line, which connected to a ADSL splitter, then modem and router.
I want to know how to isolate the RJ11 line to avoid lightning or surge, just like using an isolated transformer in some industrial factory, or is the ADSL splitter already isolated?
Thank you.

Update: Thank all of you for your helping, it seems most of you suggest there's no need for an additional isolation for protection, but won't an isolation provide cleaner signal, just like some high end audio solutions do?

 

[George Mulligan]

ADSL modems already have surge protection built in.

 

[BuddhaSkoota]

You'll need a device that provides a path to ground to dissipate a surge. A power strip-type surge protector will protect you modem from both phone line surge and electrical line surge, or you can purchase a device dedicated to the RJ11 line.

http://www.amazon.com/APC-P11VT3-Performance-SurgeArrest-Protection/dp/B0012YLTR6/ref=sr_1_6?ie=UTF8&qid=1416683501&sr=8-6&keywords=rj11+modem+surge+protection

http://www.amazon.com/CyberPower-CSP100TW-Professional-1-Outlet-Suppressor/dp/B00DR8KWBY/ref=sr_1_51?ie=UTF8&qid=1416683755&sr=8-51&keywords=rj11+modem+surge+protection

 

[westom]

I want to know how to isolate the RJ11 line to avoid lightning or surge, just like using an isolated transformer in some industrial factory, or is the ADSL splitter already isolated?.

Only myths believe an adjacent magic box (ie from amazon) will somehow block or absorb a surge. Isolation is never possible. Protection is achieved by keeping that current from approaching a modem.

Best protection at the ADSL modem is already inside that modem. Your concern is a rare transient (often less frequent than once ever seve years) that might overwhelm that protection. Protection is only possible when that transient connects to earth BEFORE entering a building. Any facility that cannot have damage always implements that well proven solution.

Remember, this is electricity. Damage only occurs when a transient has one incoming path and another outgoing path. For example, a common incoming path is AC mains. ADSL modem suffers damage only when another outgoing path to earth (ie telephone wire, ethernet cable) exists. Often, damage is on the outgoing path.

Many only use wild speculation. See damage on a telephone wire connection. Then assume that was the incoming path. Damage is often on the outgoing path to earth - ie that phone wire.

How do facilities that can never suffer damage avert that damage? Destructive surges seek eaerth ground. Protection is only provided by earthing. Any wire that enters a building without first connecting to earth means appliance damage (ie to dishwasher, computer, fire protection system, or even an ADSL modem). Neither phone wire can connect directly (hardwired) to earth. So we do a next best thing - use a protector. Critical is a low impedance (ie 'less than 3 meter') connection to earth. Every centimeter shorter increases protection.

The naive discuss protectors as if protection. Protectors are only doing what a wire would do better. How to increase protection? Upgrade the single point earth ground. Shorten that connection to earth. Power strips are not earthed - the distance is too long - excessive impedance.

That was protection only for phone lines. Protection is completely compromised if any other incoming wire is also not properly earthed. All AC wires also must be earthed by a 'whole house' protector. And again, distance and other factors are critical. If a hardwire from protector to earth is too long or has sharp bends, then the entire protection system is compromised.

Isolation transformer also does not do protection. What makes transformers effective is an earthing wire. A surge connected directly to earth by a transformer does not then connect (short circuit) the high voltage primary wire to low voltage (230 volt) household wires. Again, protection never happens by isolation. Protection is always about an item that harmlessly absorbs hundreds of thousands of joules - earth ground.

Not just any earth ground. All incoming utility wires must connect low impedance to single point earth ground. All four words have electrical significance.

 

[BuddhaSkoota]

How do facilities that can never suffer damage avert that damage? Destructive surges seek eaerth ground. Protection is only provided by earthing. Any wire that enters a building without first connecting to earth means appliance damage (ie to dishwasher, computer, fire protection system, or even an ADSL modem). Neither phone wire can connect directly (hardwired) to earth. So we do a next best thing - use a protector. Critical is a low impedance (ie 'less than 3 meter') connection to earth. Every centimeter shorter increases protection.

While a proper ground is important, it should only be considered one part of a properly protected facility. It should by no means be considered the only source of protection. Lightning can and will travel directly over any electrical or copper communication line to a home. Phone lines are certainly not only a return path, but also a direct path for lightning. Grounding at the building entrance terminal only provides a certain measure of protection. You only need to witness the destructive power of lightning to know that grounding at best might keep a house from burning down.

If you believe there is adequate protection inside a modem itself, I only suggest you perform a simple web search on the number of modems damaged by hazardous voltages due to surges or lightning. In short, there is little to no protection provided by a modem's circuits.

Surge suppression devices only provide another layer of protection. The only sure way to protect a modem from lightning is to entirely unplug them when storms are near.

 

[westom]

If you believe there is adequate protection inside a modem itself, I only suggest you perform a simple web search on the number of modems damaged by hazardous voltages due to surges or lightning. In short, there is little to no protection provided by a modem's circuits.

To challenge reality, one must intentionally misrepresent. Nobody said modems have complete protection. But modems have adequate protection - superior to what those near zero protectors claim.

All modems have serious protection. Protection that means most transients are only noise. And defined by numbers. Protection is so good that a potentially destructive transient might exist only once every seven years. A modem must withstand more than 500 volts on phone lines without damage. An industry standard that existed before PCs existed.

Concern is a rare surge that can overwhelm that protection. Adjacent protectors (ie APC or Cyberpower) do not even claim to protect from that type of transient.

How do phone companies all over the world avert damage to their $multi-million computers? Each thunderstorm means about 100 surges incoming to their switching computer. How often is your town without phone service for four days after each storm? Never? They do not waste money on adjacent protectors. Instead protectors are as close as possible to what absorbs hundreds of thousands of joules - earth ground. To increase protection, a protector is located distant from electronics - up to 50 meters. Increased separation increases protection.

A surge (ie lightning) on AC electric wires far down the street is incoming to every household appliance. Are all damaged? Of course not. An outgoing path must exist. When a surge is not earthed before entering, then modems are often victims. A surge hunted for and found earth destructively via that modem. When a modem make a best (and destructive) connection to earth.

Protection from surges is so routine that damage is traceable to human mistakes. Appliance (ie modems) already have robust protection. Protection that means most so called surges are only noise. Destructive surges hunt for earth either through appliances (ie modem) or harmlessly via a 'whole house' solution. Protection inside each appliance is not overwhelmed when a proven solution exists.

Why do telco exchanges, munitions dumps, broadcasting stations, etc all suffer direct strikes without damage? In every case, protection is defined by the quality of and connection to earth ground. Which that APC and Cyberpower recommendations do not have and will not discuss.

How do 900 joules in that Cyberpower protector absorb surges that are hundreds of thousands of joules? It doesn't. It was recommended by ignoring facts and damning numbers. That protector only claims to protect from near zero (900 joule) surges. Near zero surges made completely irrelevant by existing protection inside modems.

Surge protectors that do make a connection to earth are also known as profit centers, mythical, or scams. A protector is only as effective as its earth ground. Numbers and over 100 years of well proven science explains why facilities that cannot have damage do not waste money on those near zero protectors.

Informed consumers use well proven solutions that connect low impedance (ie 'less than 3 meters') to what actually does protection. A protector is only as effective as its earth ground. Numbers demonstrate why.

One who first learned this stuff would say why some modems are damaged. How do near zero joules provide protection? They don't. Many do not even know of proven protection installed by telcos for free on every incoming telephone wire. But somehow a naive consumer knows advertising must be honest. As if 900 joules will somehow absorb a surge that is hundreds of thousands of joules.

 

[BuddhaSkoota]

To challenge reality, one must intentionally misrepresent.

Hey, check this one out...it's got a little pig-tail thingy on it! You can't tell me this won't protect a modem from a bajillion volts.

 

[westom]

You can't tell me this won't protect a modem from a bajillion volts.

One must learn basic electrical concepts before making recommendations or conclusions. Lightning only tries to achieve a billion volts if someone foolishly tries to stop it (ie the APC or Cyberpower recommendation). Surge (ie lightning) is a current sources; not a voltage source as so many assume. That means voltage only rises if someone foolishly tries to block it.

Lightning is typically 20,000 amps. So effective protection starts at about 50,000 amps. View a ground wire found on a 50,000 amp protector. Typically 12 gauge (2 mm diameter). That means a direct lightning strke without damage to a protector or its wire connection to earth.

Effective protection means nobody even knew a surge existed. Even a protector must not fail. Other concepts apply. It says why an ADSL modem is only damaged when the homeowner does not learn of and install these well proven (and less expensive) solutions. Only urban myths and their purveyors claim lightning will put a billion volts in the house. Since the naive would not even know what current sources are.

 

[sam1275tom]

Thank all of you for your helping, it seems most of you suggest there's no need for an additional isolation for protection, but won't an isolation provide cleaner signal, just like some high end audio solutions do?

 

[westom]

Thank all of you for your helping, it seems most of you suggest there's no need for an additional isolation for protection, but won't an isolation provide cleaner signal, just like some high end audio solutions do?

Appreciate how electronics work. Incoming power (maybe 120 VAC) is filtered. Then increased to well over 300 volts. Then converted to high voltage radio freequency spikes. Now that electricity is 'dirtier' than anything seen on AC mains. Then those high frequency spikes are filtered and convert to low (ie 5) voltage DC that is rock solid and stable. All due to superior 'cleaning' and 'isolationi' circuits already inside electronics.

Any 'cleaning' or isolatioin done on a power cord is completely undone inside electronics. Then superior 'cleaning' and isolation circuits inside electronics perform a superior job.

Why would some expensive device on its power cord do anything better? Read spec numbers. Most 'cleaning' or 'isolation' devices do not make claims that so many only assume. These devices are highly recommended when feelings make technical decisions. Many recommend those devices due to brainwashing - also called advertising and hearsay.

Previously defined was a rare anomaly that overwhelm superior and existing isolation and 'cleaning' circuit. A solution must be located elsewhere. And costs about $1 per protected appliance. Notice the best solutions actually cost less money. Notice the only useful recommendations always say so with numbers and other technical facts. Subjective claims are typical of junk science and scams.

A three dollar power strip with ten cent protector parts can be sold to naive consumers for $80 and $120. Many assume a higher price means better quality. A power strip with similar spec numbers also sells in big box storesor $10. Scams are easily pro\moted when one recommends something without first learning specification numbers and how things work.

ADSL modems are rarely harmed by anomalies incoming onthe telephone line. ADSL modems are often damage by anomalies from AC mains. In part, because superior protection is already installed for free by the telco. Required reasons why were provided perviously.

Never ask in terms of subjective and all but usefess expressions such as 'isolation' or 'dirty'. Solution only exist when discussion is about each anomaly (ie frequency variation, harmonics, EMC/EMI, floating neutral, power factor, sag, blackout, polarity reversal, etc). Valid solutions that should concern you were defined with numbers.

Now, which anomaly so concerns you as to need 'isolation'?