Ethernet port fried by lightning - any fix?

Discussion in 'Mac mini' started by johngwheeler, Dec 4, 2014.

  1. johngwheeler macrumors 6502

    Dec 30, 2010
    I come from a land down-under...

    We had a storm a couple of days ago, and I found that my cable modem / router, Apple Airport Extreme and the Ethernet port of my Mac Mini (connected to the router) were all damaged.

    Just wondering if it is possible (or economically worthwhile) to fix the Ethernet network adapter on my Mini (2011 quad-core), or whether this involves replacing the entire logic board?

    The workaround is to use the Thunderbolt port with an adapter, but then I lose the ability to run two monitors (without USB 2 adapters).

    I'm surprised just how easily damaged LAN ports are - the electrical surge passed through the cable, the modem and at least two of the connected devices.

    This is the second time I lost both a cable modem and an Apple Airport - is there any effective way of preventing this (other than unplugging, and I'm not always at home when it happens!). I have a power surge protector, but I doubt this prevents surges that happen through the overhead co-ax cable.
  2. chabig macrumors 601

    Sep 6, 2002
    I lost an ethernet port to a lightning strike years ago. Check with your homeowner's insurance. It might be covered. You'll probably need a new logic board if you want that port back.
  3. Rodster macrumors 68040

    May 15, 2007
  4. monokakata macrumors 68000


    May 8, 2008
    Hilo, Hawai'i
    There definitely are surge protectors for both ethernet cable and RG coax.

    The downside for the RG ones are that you lose a bit of signal strength.

    For the ethernet ones, there are no downsides that I'm aware of.

    When I lived in lightning-strike country I ran the ethernet cable from the cable modem through a surge protector on a strip (I don't have it and can't remember the brand, but it might have been APC) -- a simple in-and-out connection.

    What this won't protect from would be some kind of strike on the house with enough energy to get into whatever ethernet cables you have running around the house, if any. That could cause a surge downstream from the protector.

    The coax protector was a second unit.
  5. johngwheeler thread starter macrumors 6502

    Dec 30, 2010
    I come from a land down-under...
    Thanks! This is useful information. I'll be looking for these items before the next storm!
  6. jod1921 macrumors member

    Jun 17, 2009
    No Ethernet means no App Store or OS X downloads. The Ethernet port is used to identify your computer to the App Store. I know all about it. It won't let you sign in anymore. The usb Ethernet adapters all work great.
  7. Micky Do macrumors 68000

    Micky Do

    Aug 31, 2012
    An island in the Andaman Sea.
    I'm not surprised at all.

    It is the reason folks around these parts always use a UPS. In addition to providing 10 - 20 minutes of back up in the event of a power cut (quite common here) a UPS provides surge protection, and has ports for the ethernet as well as electric power plugs.

    As such, I cannot offer any advice for a problem I have not experienced; just making a suggestion to avoid the problem in future.

    My first UPS was fried by a massive surge that knocked out power to half of Thailand's South. The computer survived, but the power supply failed after only four years, I guess because of dealing with widely fluctuating mains power voltage. I am at the end of a line, and at the time kicking fluorescent lights into action often didn't happen.

    Since then the mains line and transformer has been upgraded, I have installed an earth (so now use three pin plugs), and I replaced my original UPS with one that has AVR (Auto Voltage Regulation)…. and got a new Mini in 2009 (more cost effective than repairing the 2005 original). All is been well now, with the UPS on to its third battery (they are good for 2 - 3 years), and no surge damage to anything for years.
  8. westom macrumors regular

    Nov 8, 2009
    Ethernet ports are some of the most robust. To be damaged, you have connected over 2000 volts through it. Why is that surge current anywhere inside a house?

    Direct lightning strikes without damage are routine IF having learned concept originally demonstrated in 1752 by Franklin. What does lightning seek? We were taught this in elementary school science. Earth ground. Why did you have electronics damage? You gave lightning a best connection to earth destructively via modem, ethernet port, etc. And yes, surge damage is so easily averts as to be considered a human mistake.

    Protection means every entering wire makes a low impedance (ie 'less than 10 foot') connection to single point earth ground. Cable is required by code to have a hardwire connection. But only you are responsible for providing and maintaining that single point earth ground. No earth ground means no protection. An expression low impedance is also critically important.

    Other incoming wires (telephone, AC electric) cannot connect directly to earth. So we install a protector to do what a hardwire does better. Again, that connection must be low impedance (ie no sharp bends). Like cable, your telephone already has a 'whole house' protector installed for free by the telco. Did you destroy protectoin by not maintaining that earth ground?

    Protection means you can say where hundreds of thousands of joules harmlessly dissipate. That means a surge current connects to earth without even entering the buildling. Unfortunately, the most common source of surges (AC electric) is not required to have earthed protection. A lightning strike far down the street is a direct strike incoming to every household appliance. If a 'whole house' protector for AC mains is not earthed, then you have all but invited lightning to go hunting destructively inside.

    An excellent path to earth is incoming on AC mains. Into a computer. Out via its ethernet port. Through modem. To earth via the telco or cable company's protection. A damaged ethernet port means that was the outgoing path - not an incoming surge path as so many assume using speculation.

    You know this from elementary school science. To have electricity, both an incoming and outgoing path must exist. And you know a cloud connected to earth destructively via your computer. Direct lightning strikes without damage even to a protector have been routine for over 100 years. But that means learning why you all but invited that current to find earth destructively. And installing a well proven and earthed solutions.

    Earthing is not a wall receptacle. Impedance (ie 'less than 10 foot') makes that obvious. No UPS or power strip claims such protection. In some cases, an adjacent protector even compromises protection inside modems, routers, and computers.

    So which AC, telephone, or cable wires entered without a low impedance connection to earth? Do you have a single point earth ground (all four words have electrical significance)? Your damage is due to a surge current all but invited inside the building. Obviously plug-in recommendations mean that current is inside. Effective protection would not exist.

    Much to learn. Including why receptacle (power point) safety ground is not earth ground. Why a UPS, AVR, power conditioner, or protector strip is all but useless. And most improtant, protection is always about where hundreds of thosuands of joules harmlessly dissipates.

    Start by reporting what currently exists.
  9. Fishrrman, Dec 5, 2014
    Last edited: Dec 5, 2014

    Fishrrman macrumors G5


    Feb 20, 2009
  10. johngwheeler thread starter macrumors 6502

    Dec 30, 2010
    I come from a land down-under...
    This doesn't happen in my case. The Ethernet port appears dead - always shows "not connected" even when connected with working cable to another working port. I'm (fortunately) still abel to log in to the App Store and update.
  11. johngwheeler thread starter macrumors 6502

    Dec 30, 2010
    I come from a land down-under...
    I'm sure there's some good advice in this rather "grammatically stilted " reply, which I'm trying to decipher :)

    Lack of earthing is obviously a big problem, particularly when the path to earth is via my expensive electronics - I love the smell of burning components in the morning....

    Part of my problem is that there is a long suspended cable run from the street to my house. The cable provider does not appear to include any surge protection for the cable or its termination in my house. This is something I'm trying to remedy at my own cost by acquiring a UPS with surge protection. Should I have done more earlier? Absolutely, but cost and time are always a consideration in life. Now I'm regretting it, but then again, I've never had this experience before. I hope not to have it again!

    I wasn't at home when the damage occurred, so I don't know what happened, although I doubt I suffered a direct lightning strike (I live in suburban Sydney, not in the Outback). However, it must have been a pretty significant electromagnetic event to fry to so many components in the wired chain.

    Now I know how easily this kind of "disaster" can happen, I'll be better prepared next time!


    I've got a fried Ethernet port on my Mini after a nearby lightning strike. I imagine that this would require an entire logic board replacement to fix.

    Does anyone know how much this costs (approximately)? Is it even worth it given the possibility of using USB or Thunderbolt adapters for Ethernet?


  12. TPadden macrumors 6502a

    Oct 28, 2010
    Don't bogart that joint, my friend .......:cool:
  13. westom macrumors regular

    Nov 8, 2009
    Tie a knot in wires. That is also surge protection using another's reasoning. A UPS, a knot, or some magic box is near zero protection.

    Previous post demonstrated many times over why a UPS does not protect from typically destructive surges. A UPS does not claim and does not do surge protection. Or read its numeric specs. How many joules does it claim to absorb? Hundreds? A destructive surge means hundreds of thousands of joules must dissipate somewhere. Either harmlessly outside. Or destrutively inside the building because the only 'protector' was near zero AND adjacent to appliances.

    Protection is not a protector. Effective protectors are connecting devices doing what a hardwire does better. Your cable must have that hardwire (low impedance) connection to earth. A connection that must also exist for human safety as well as for transistor safety. Ineffective protector (ie a UPS) does not have and cannot have that connection to earth. (Do not confuse safety ground with earth ground.) Protection absorbs hundreds of thousands of joules so that no one even knew a surge existed.

    All this applies to both underground and overhead utility cables.

    What other items were damaged? What utility wire did each damaged item connect to? Learn from damaged items why a surge, incoming to everything, only damaged some things. That knowledge will further define how robust your corrective measures must be.

    Another solution for that computer is to plug an Ethernet NIC into that computer. And disable the motherboard based Ethernet port so that the OS is not confused by trying to connect to a defective port.
  14. Cape Dave macrumors 68000

    Nov 16, 2012
    Another thing most do not know. A surge protector only works once. It uses up what it has to protect, at which point you must get another new unit.

    This is true for most, maybe not all surge protectors. (there may be some new types I am not aware of) but this is generally true.

    Kind of like it gives its life to protect your computer :)
  15. Southern Dad macrumors 65816

    Southern Dad

    May 23, 2010
    Shady Dale, Georgia
    You are using an AirPort Extreme and a Mac Mini, why not connect via WiFi and not worry about the ethernet port?

    Since you have cable for your internet, I'd go outside and check the splitter attached to the side of your house. Is the ground wire still attached? Follow it all the way to the ground. Is it actually connected to anything that is grounded? You've been hit twice. As other posters have posted but using big technical words, something needs to be looked at.

    A few years ago, the distribution utility pole at the top of the hill took a direct lightning hit, then burned. Most of us on this street lost nothing. One neighbor, who is farther away from the strike than myself had a television that literally had burn marks on the back of it. His cable connection on the side of the house? Not grounded. BTW - the cable company bought him a new television, it seems that poles ground wire was missing and they hadn't fixed it. Copper thieves.
  16. Celerondon macrumors 6502a


    Oct 17, 2013
    Southern Cal
    Yes There Is A Way To Prevent This Problem!

    Westom is correct. You are also right about the surge protectors. They are an important part of a surge protection system but as westom said, they can't stop the big stuff. If you do not identify and solve the weaknesses in your power supply, communications, and other residential systems, these problems or worse ones are likely to repeat.

    The Institute of Electrical and Electronics Engineers (IEEE) has published a basic guide to surge protection, How To Protect Your House and Its Contents From Lightning.

    Although everyone should pay attention to these essential systems, often the hardware involved goes decades without inspections or maintenance. Last summer my quick check of a (telephone) Network Interface Device (NID) revealed that the ground rod was not connected to the telephone hardware. The telephone technicians fixed the problem after I mentioned it. I do not know if the repairs would have occurred if I had not known what to look for.

    Call a contractor if you are not able to complete the required inspections to verify that you have protection beyond simple "point of use" devices such as surge protectors or UPS systems.

    Some pioneering work on this subject was performed by Benjamin Franklin.

    Attached Files:

  17. johngwheeler thread starter macrumors 6502

    Dec 30, 2010
    I come from a land down-under...
    I prefer not to use wi-fi because I do a lot of network file transfers between computers on my LAN and the Gigabit Ethernet is significantly faster! It also reduces possible wi-fi bandwidth contention from all all the other connected devices in the house (2 computers, 3 phones, 2 adds up!).

    Good advice re checking the ground connection - I have a feeling the "cable guy" who set it up wasn't the sharpest tool in the shed.
  18. westom macrumors regular

    Nov 8, 2009
    Appreciate the problem. Most electricians and linemen need not know how electricity works. They are taught what must connect to what. And rarely told why.

    I was sitting with two cable company linemen who had just come from their company's training session. As I explained why this must be done, one kept turning to the other and saying, "That's what they were talking about." Unfortunately many have difficulty understanding this stuff the first time due to myths and outright deception that so many are taught by advertising and hearsay. For example, many do not understand why resistance and impedance are different. And why the difference is so relevant.

    An IEEE brochure cited by Celerondon summarized much of what I posted without saying why. Page 42 Figure 8 happens when a surge is not connected to earth at the service entrance. A plug-in protector then connects an 8000 volt surge destructively through an adjacent TV. Once that surge is inside, then it will hunt for and find earth ground destructively via appliances. A plug-in protectors only gave it more potentially destructive paths.

    Plug-in protectors are useful when supplementing a properly earthed 'whole house' solution. Without an earth ground, then plug-in protectors are useless for a destructive type surges - as demonstrated in Figure 8. Earth ground with a short connection is critical. Otherwise adjacent protectors may even bypass protection already inside computers.

    Most important aspect of any protection system: single point earth ground and a connection to it. Electricians and linemen understand that lower resistance is achieved with a thicker wire. But low resistance is not significant. Relevant term is "low impedance". Lower impedance means a shorter wire; not necessarily a thicker wire. And a wire without splices or sharp bends. Some electricians and linemen eventually learn this. But many do not since the reasons why are not provided.

    Protection is always defined what what absorbs hundreds of thousands of joules - earth ground. Any solution that ignores that so important system component implies myths or an outright scam. Earthing is critical.

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