Archive for October, 2009

Knob-and-tube wiring, what you should know

October 20th, 2009 No comments

Electrical Tip of the Day: Knob and tube electrical wiring was installed in homes from the 1920’s to the mid 1960’s – later in some rural locations.  As indicated by the name the instillation method used a combination of porcelain “knobs” and “tubes” as insulators to install the wire.  Here are the basic characteristics of a knob and tube wiring system:

  • No ground: Only a hot and neutral wire are used… the circuit does not have a ground conductor
  • Wire insulation: Electrical wires are wrapped in a rubberized cloth or ascroll fiber insulation.  In some cases a second rubber / fiber insulator was also slid over the primary conductors.
  • Connections or splices were made outside of electrical junction boxes, typically by twisting the wire at a “tap” point, soldering the connection, and insulating it with tape.
  • Hot and Neutral conductors separated on framing member:  Hot and neutral conductors were not in a common cable like modern romex wire.  They were separated onto opposite sides of framing members.


What you should know.  Currently the NEC code and most local jurisdictions do not specifically say that knob and tube wiring is illegal, however they do have some very specific requirements if it is to be left installed and in use (NEC 2008 – article 394). Here are the basic guide lines that must be followed:

  • Over current protection to be on hot conductors only
  • Over current protection not to exceed 15 amps
  • No open splices – original splices may remain if soldered and insulated with tape
  • New extension wire connections to be made in junction boxes
  • Knob and tube wiring to be supported only by non-conductive stand off supports – it may not be secured in contact with combustible materials
  • Knob and tube wiring is only rated to be used in free air, un-insulated spaces.  It is not permitted to have knob and tube wiring covered or concealed by insulation of any kind


So what makes knob and tube such a major safety concern today?   What it really comes down to is that it does not have a ground, the age of the conductor insulation, changes to the building or original installation (such as the way it has been spliced), and the addition of building insulation over or around the knob and tube.  Here are the key concerns:

  • No electrical ground: The circuit is only comprised of a “hot” and a “neutral” conductor – making it less safe than a modern grounded electrical circuit.  Devices that use a grounded plug (three prong) should not be connected on an un-grounded circuit, specifically appliance loads.
  • Damage : In most cases knob and tube is past the “safe” useable life span. Heat damage, cracked and rotten insulation, exposure to leaks, cracked or missing insulators, chewing rodents, or damage from being steeped on all add up over time.  We don’t find much knob and tube that is in safe useable condition.
  • New work and open splices: We often find improper “new” extensions added to original knob and tube circuits.  Electrical splices are to be made in an approved junction box per NEC code.  The very basic reason for this is to contain a fire if the junction fails.
  • Building insulation: The fire safety of knob and tube wiring relied on the fact that the wires were typically separated on framing members, suspended in free air between knobs, and passed thru combustible materials in ceramic tubes. Where original conductors were installed in walls or in attic floors, and where then later covered in building insulation, the knob and tube wires then no longer meet code.  They can become hotter than intended, and may be a fire hazard due to the proximity to combustible materials.
  • Switched Neutral: It was the excepted install practice at the time to switch the neutral conductor on a knob and tube circuit.  It poses a increased risk for homeowners to have switched neutrals.  A switch can be in the off position and still have full voltage at the load (like a light fixture). Switched neutrals on a circuit can also cause voltage irregularities that can effect today’s sensitive modern electronics.
  • Homeowners insurance: Most homeowner’s insurance policies have specific language regarding knob and tube wiring.  Is some cases they call for its removal in order for the policy to be valid.  In other cases there may be increased rates and/ or changes in coverage.  If your home has knob and tube wiring you will want to specifically ask your insurance agent how this affects your coverage.

So, that was a lot to digest.  If you have questions or concerns about knob and tube I would be happy to answer them for you.  Contact me here or thru the Artisan web page.

Electrical Tip of the Day: Updating your lighting, 5 things you must know

October 14th, 2009 No comments

In many of the homes built in the late 80’s and 90’s little attention was paid to the lighting.  Likewise, historic homes and one-of-a-kind custom homes often share a common problem… bad lighting design and layout.  So here are 5 tips to help you out with some potential lighting updates.

#1 – There are no rules! You can do whatever you want… like anything else the lighting in your home can and should be a statement about you.  Some folks prefer lighting that stands out and is a point of interest in a room, others prefer lighting that is ambient and becomes “part of the space”.  Either way is fine – but do not be afraid to be daring.  Chandelier in the bathroom?  Why not!  Really like that historic fixture?  Get it restored!

#2 – Sconce Lights and table lamps can be your friend! Lighting in a room tends to look better and more interesting when it comes from multiple sources.  A combination of ceiling lights, wall mounted sconces, and table lamps can really help get the look and feel of a home dialed in.  I am a big fan of adding sconce lights to living rooms and dining rooms.  This can be a very cost effective way to spruce up a space and really change the look of a room, both with the fixtures themselves and the layering of the light.

#3 – Kitchen lights can be cool too! As I said earlier, there are no rules.  Nothing says that you have to keep that old fluorescent  surface mount light in the center of the kitchen anymore…  and those old can lights over the bar with the yellow stained “eye ball” trims, maybe it’s time to retire them.  A combination of under cabinet lights, pendant lights, reseeded can lights, and hidden “nook” ambient lighting can make a huge difference in a kitchen.   Many of these changes can be done on a tight budget, and in most cases can be done in several phases to spread the cost out into affordable bites.

#4 – Outside lighting sets the mood! No matter what time of year it is the exterior lighting on your home is the mood setter.  At night when you come and go it is the most striking visual feature of your home, embrace it.  There are a lot of considerations for exterior lighting… be it security, landscape lighting, architectural feature lighting, lot lighting, path and drive way lighting, and so on.  As with lighting in the interior of the home “layering” your exterior lighting is the secret.  Using the structure of the home, the landscape, the decks and garages, and any other building feature to get varied elevations of light really brings things to life.  Here is another quick tip – landscape lighting always looks better when done in non-symmetrical layouts, with several different types of fixtures and lamp types.  If you are sporting the “runway” landing strip lights down your front sidewalk let’s talk.

#5 – Dimmers, Dimmers, Dimmers! The amount of ambient light that comes in a home changes with the seasons, the weather, the time of day… and so too does all of our moods.  Being able to dim the lights in a given space is one of the quickest affordable changes that can be made to dramatically affect the lighting in a space.   The light level needed in a room to play a quality game of RISK with the family is certainly not the ideal amount of light needed for movie night (especially if it is scary move night) – dimmers to the rescue.  I also find that installing dimmers for your exterior lighting is a very cool and helpful way to dial in the look of a patio or outdoor living space.

Where are the cool fixtures at?

October 7th, 2009 No comments

Check this stuff out… one of my favorite full line lighting suppliers / ceiling fan makers.  I love their products, top quality and a wide range of styles. Their ceiling fans are some of the best made and their designer line by George Kovacs is very cool stuff (FYI – Kirby Risk is a dealer, which gives us local support on products and better pricing).

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Light Fixture Restoration – is it time for a checkup?

October 6th, 2009 No comments

Electrical Tip of the Day:  Like everything else, light fixtures need maintenance too.  Failure to maintain old fixtures can, and does, cause fires; as well as representing a high risk of electrical shock to the homeowner.  Many of the products used to make old (vintage) fixtures are long past the point of safety and need to be replaced, especially ones with cloth insulated wire and cardboard insulated lamp sockets. That said many of these vintage fixtures simply cannot be replaced and have a charm that is hard to live without.

So what do you do?  One good option is to restore them.  Restoration can give you the option of keeping the old fixtures but updating them with modern products to keep you and your family safe.

The warning signs… do your fixtures need some restoration attention?  Look for frayed, cracked, or peeling exposed wire, burnt or charred lamp sockets, fixtures that hum or flicker, and fixtures that seem to burn out a lot of lamps.  Any fixture that is older then 30 years should be looked at.

So what does a full restoration cover?  Typically we would remove the fixture, replace all the old wire, install new solid porcelain lamp sockets, give it a good cleaning (being careful not to destroy the patina), check / re-wire the junction box where it was installed for problems, then re-install.

Here are some examples of a restoration project we have underway now (note the old socket being replaced as it was actually starting to arc and burn at the bottom – this is a pretty common condition that occurs after years of use, high wattage lamps, and the lamps being over tightened to “make them work”).

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Portable Electrical Heaters – safety and use

October 1st, 2009 No comments

Electrical Tip of the Day:  The number #1 cause of electrical house fires in the US is the misuse of portable electrical space heating equipment.  The truth of the matter is that these things have a pretty high degree of danger associated with them that many people are just not fully aware of.  Here are a few quick tips:

  • Do not use them on extension cords, and if you must – use a grounded #12 gauge cord that is just long enough to do the job
  • Make sure the heater is not on a circuit that already has a large load on it. A 1500 watt heater on high will draw as much as 13 amps.  If you are using a 15 amp circuit that is really only supposed to be run at 80%  (per NEC code) the heater alone puts you at the limit of the permissible load rating of the circuit
  • Do not plug in other cords into the same outlet as a heater.  Most outlets are only rated for 15 amps, so adding an additional load could be the straw that breaks the camel’s back
  • Do not use space heaters on wiring systems that have not been upgraded to ground 3 wire circuits and modern toggle style breakers.  Most of these old systems were not design for these kinds of loads
  • Ideally space heaters should be used on 20 amp circuits that does not share power with the lighting system or other outlet loads
  • If the heater keeps tripping the circuit, then don’t “force” the breaker back into reset.  It is tripping for a reason and a larger problem could be in progress
  • Use heaters of a “sealed” design – such as the portable electric radiator type.  They do not have exposed elements that can ignite combustible materials
  • Make sure your heater has a UL listing for safety and has an automatic shut off device in case it gets knocked over – if it does not it is time for a new heater
  • Do not use plug adapters and multi-outlet plug strips with electric heaters
  • Never leave a heater unattended with pets and small children
  • Make sure you have working smoke detectors and fire extinguishers in your home, ALWAYS!

If you have any questions on how to safely use space heaters in your home or office give us a call – we would be happy to get you on the right track.