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Frequently Asked Questions (FAQS);faqs.032



    The two pairs of connections on a GFCI outlet are not symmetric.
    One is labeled LOAD; the other, LINE.  The incoming power feed
    *must* be connected to the LINE side, or the outlet will not be
    protected.  The LOAD side can be used to protect all devices
    downstream from it.  Thus, a whole string of outlets can be
    covered by a single GFCI outlet.

Subject: Where should GFCIs be used?

    The NEC mandates GFCIs for 110V, 15A or 20A single phase
    outlets, in bathrooms, kitchens within 6' of the sink, garages,
    unfinished basements or crawl spaces, outdoors, near a pool, or
    just about anywhere else where you're likely to encounter water
    or dampness.  There are exceptions for inaccessible outlets,
    those dedicated to appliances ``occupying fixed space'',
    typically refrigerators and freezers, and for sump pumps and
    laundry appliances.

    The CEC does not mandate as many GFCIs.  In particular, there
    is no requirement to protect kitchen outlets, or most garage or
    basement outlets.  Basement outlets must be protected if you
    have a dirt floor, garage outlets if they're near the door to
    outside.  Bathrooms and most exterior outlets must have GFCIs.

    Even if you are not required to have GFCI protection, you may
    want to consider installing it anyway.  Unless you need a GFCI
    breaker (see below), the cost is low.  In the U.S., GFCI
    outlets can cost as little as US$8.  (Costs are a bit higher in
    Canada:  C$12.)  Evaluate your own risk factors.  Does your
    finished basement ever get wet?  Do you have small children?
    Do you use your garage outlets to power outdoor tools?  Does
    water or melted snow ever puddle inside your garage?

Subject: Where shouldn't I use a GFCI?

    GFCIs are generally not used on circuits that (a) don't pose a
    safety risk, and (b) are used to power equipment that must run
    unattended for long periods of time.  Refrigerators, freezers,
    and sump pumps are good examples.  The rationale is that GFCIs
    are sometimes prone to nuisance trips.  Some people claim that
    the inductive delay in motor windings can cause a momentary
    current imbalance, tripping the GFCI.  Note, though, that most
    GFCI trips are real; if you're getting a lot of trips for no
    apparent reason, you'd be well-advised to check your wiring
    before deciding that the GFCI is broken or useless.

Subject: What is the difference between a GFCI outlet and a GFCI breaker?

    For most situations, you can use either a GFCI outlet as the
    first device on the circuit, or you can install a breaker with
    a built-in GFCI.  The former is generally preferred, since GFCI
    breakers are quite expensive.  For example, an ordinary GE
    breaker costs ~US$5; the GFCI model costs ~US$35.  There is one
    major exception:  if you need to protect a ``multi-wire branch
    circuit'' (two or more circuits sharing a common neutral wire),
    such as a Canadian-style kitchen circuit, you'll need a
    multi-pole GFCI breaker.  Unfortunately, these are expensive;
    the cost can range into the hundreds of dollars, depending on
    what brand of panel box you have.  But if you must protect such
    a circuit (say, for a pool heater), you have no choice.

    One more caveat -- GFCI outlets are bulky.  You may want to use
    an oversize box when installing them.  On second thought, use
    large (actually deep) boxes everywhere.  You'll thank yourself for it.

    Incidentally, if you're installing a GFCI to ensure that one
    specific outlet is protected (such as a bathroom), you don't
    really have to go to all of the trouble to find the first
    outlet in the circuit, you could simply find the first outlet
    in the bathroom, and not GFCI anything upstream of it.  But
    protecting the whole circuit is preferred.

    When you install a GFCI, it's a good idea to use the little
    "ground fault protected" stickers that come with it and mark
    the outlets downstream of the GFCI.  You can figure out which
    outlets are "downstream", simply by tripping the GFCI with the
    test button and see which outlets are dead.

Subject: What's the purpose of the ground prong on an outlet, then?

    Apart from their use in electronics, which we won't comment on,
    and for certain fluorescent lights (they won't turn on without
    a good ground connection), they're intended to guard against
    insulation failures within the device.  Generally, the case of
    the appliance is connected to the ground lead.  If there's an
    insulation failure that shorts the hot lead to the case, the
    ground lead conducts the electricity away safely (and possibly
    trips the circuit breaker in the process).  If the case is not
    grounded and such a short occurs, the case is live -- and if
    you touch it while you're grounded, you'll get zapped.  Of
    course, if the circuit is GFCI-protected, it will be a very
    tiny zap -- which is why you can use GFCIs to replace
    ungrounded outlets (both NEC and CEC).

    There are some appliances that should *never* be grounded.  In
    particular, that applies to toasters and anything else with
    exposed conductors.  Consider:  if you touch the heating
    electrode in a toaster, and you're not grounded, nothing will
    happen.  If you're slightly grounded, you'll get a small shock;
    the resistance will be too high.  But if the case were
    grounded, and you were holding it, you'd be the perfect path to
    ground...

Subject: Why is one prong wider than the other?  Polarization

    Nowadays, many two-prong devices have one prong wider than the
    other.  This is so that the device could rely (not guaranteed!)
    on one specific wire being neutral, and the other hot.
    This is particularly advantageous in light fixtures, where the
    the shell should neutral (safety), or other devices which want to
    have an approximate ground reference (ie: some radios).

    Most 2-prong extension cords have wide prongs too.

    This requires that you wire your outlets and plugs the right
    way around.  You want the wide prong to be neutral, and the
    narrow one hot.  Most outlets have a darker metal for the
    hot screw, and lighter coloured screw for the neutral.
    If not, you can usually figure out which is which by which
    prong the terminating screw connects to.

Subject: What kind of outlets do I need in a kitchen?

    The NEC requires at least two 20 amp ``small appliance
    circuits'' for kitchens.  The CEC requires split-duplex
    receptacles.  Outlets must be installed such that no point is more
    than 24" (NEC) (900 mm CEC) from an outlet.  Every counter wider
    than 12" (NEC) or 300 mm (CEC) must have at least one outlet.
    The circuit these outlets are on may not feed any outlets except
    in the kitchen, pantry, or dining room.  Furthermore, these circuits
    are in addition to any required for refrigerators, stoves, microwaves,
    lighting, etc.  Non-dedicated outlets within 6' of a sink *must* be
    protected by a GFCI (NEC only).

    Split duplex receptacles are fed with a 220V circuit.  The tab
    is broken on the hot side of the outlet, and one hot goes to
    the upper outlet, and the other hot goes to the lower outlet.
    The neutral connects to both outlets through one screw.  When
    "carrying through" to another outlet, the neutral must be
    pigtailed, such that removing the outlet, or having the neutral
    connection fall off doesn't cause the neutral to disconnect
    from downstream outlets.

Subject: Where must outlets and switches be in bathrooms?

    There must be at least one outlet in each bathroom, adjacent to
    the sink, in addition to any outlet that may be incorporated in
    the light fixture.  All such outlets *must* be GFCI-protected.

Subject: What is Romex/NM/NMD?  What is BX?  When should I use each?

    Romex is a brand name for a type of plastic insulated wire.
    Sometimes called non-metallic sheath.  The formal name is NM.
    This is suitable for use in dry, protected areas (ie: inside
    stud walls, on the sides of joists etc.), that are not subject
    to mechanical damage or excessive heat.  Most newer homes are
    wired almost exclusively with NM wire.  There are several
    different categories of NM cable.

    BX cable -- technically known as armored cable or "AC" has a
    flexible aluminum or steel sheath over the conductors and is
    fairly resistant to damage.

    TECK cable is AC with an additional external thermoplastic
    sheath.

    Protection for cable in concealed locations: where NM or AC cable
    is run through studs, joists or similar wooden members, the outer
    surface of the cable must be kept at least 32mm/1.25" (CEC & NEC)
    from the edges of the wooden members, or the cable should be protected
    from mechanical injury.  This latter protection can take the form of
    metal plates (such as spare outlet box ends) or conduit.

    [Note: inspector-permitted practise in Canada suggests that armored
    cable, or flexible conduit can be used as the mechanical protection,
    but this is technically illegal.]

    Additional protection recommendations (these are rules in the
    Canadian codes - they are reasonable answers to the vague
    references to "exposed to mechanical damage" in both the NEC
    and CEC):

        - NM cable should be protected against mechanical damage
          where it passes through floors or on the surface of walls
          in exposed locations under 5 feet from the floor.
          Ie: use AC instead, flexible conduit, wooden guards etc.
        - Where cable is suspended, as in, connections to furnaces
          or water heaters, the wire should be protected.  Canadian
          practise is usually to install a junction or outlet
          box on the wall, and use a short length of AC cable
          or NM cable in flexible conduit to "jump" to the appliance.
          Stapling NM to a piece of lumber is also sometimes used.
        - Where NM cable is run in close proximity to heating
          ducts or pipe, heat transfer should be minimized by
          means of a 25mm/1" air space, or suitable insulation
          material (a wad of fiberglass).
        - NM cable shall be supported within 300mm/1' of every box
          or fitting, and at intervals of no more than 1.5m/5'.
          Holes in joists or studs are considered "supports".
          Some slack in the cable should be provided adjacent to
          each box.  [while fishing cable is technically in violation,
          it is permitted where "proper" support is impractical]
        - 2 conductor NM cable should never be stapled on edge.
          [Knight also insists on only one cable per staple, referring
          to the "workmanship" clause, but this seems more honoured
          in the breach...]
        - cable should never be buried in plaster, cement or
          similar finish.
        - cable should be protected where it runs behind baseboards.
        - Cable may not be run on the upper edge of ceiling joists
          or the lower edges of rafters where the headroom is more
          than 1m (39").

    Whenever BX cable is terminated at a box with a clamp, small
    plastic bushings must be inserted in the end of the cable to
    prevent the clamps forcing the sharp ends of the armor through
    the insulation.

    BX is sometimes a good idea in a work shop unless covered by
    solid wall coverings.

    In places where damage is more likely (like on the back wall of
    a garage ;-), you may be required to use conduit, a
    UL- (or CSA-) approved metal pipe.  You use various types of
    fittings to join the pipe or provide entrance/exit for the
    wire.

    Service entrances frequently use a plastic conduit.

    In damp places (eg: buried wiring to outdoor lighting) you will
    need special wire (eg: CEC NMW90, NEC UF).  NMW90 looks like
    very heavy-duty NMD90.  You will usually need short lengths of
    conduit where the wire enters/exits the ground.  [See underground
    wiring section.]

     Thermoplastic sheath wire (such as NM, NMW etc.) should not be
     exposed to direct sunlight unless explicitly approved for that
     purpose.

     Canada appears to use similar wire designations to the US,
     except that Canadian wire designations usually include the
     temperature rating in Celsius.  Eg: "AC90" versus "AC".
    In the US, NM-B is 90 degrees celcius.

    NOTE: local codes vary.  This is one of the items that changes
    most often.  Eg: Chicago codes require conduit *everywhere*.
    There are very different requirements for mobile homes.
    Check your local codes, *especially* if you're doing anything
    that's the slightest out of the ordinary.

    Wire selection table (incomplete - the real tables are enormous,
    uncommon wire types or applications omitted)

    Condition            Type    CEC    NEC

    Exposed/Concealed dry        plastic    NMD90    NM
                    armor    AC90    AC
                        TECK90

    Exposed/Concealed damp        plastic    NMD90    NMC
                    armor    ACWU90
                        TECK90

    Exposed/Concealed wet        plastic    NMWU90
                    armor    ACWU90
                        TECK90

    Exposed to weather        plastic    NMWU
                        TW etc.
                    armor    TECK90

    Direct earth burial/        plastic    NMWU*    UF
    Service entrance            RWU
                        TWU
                    armor    RA90
                        TECK90
                        ACWU90
    [* NMWU not for service entrance]


Subject: Should I use plastic or metal boxes?

    The NEC permits use of plastic boxes with non-metallic cable
    only.  The reasoning is simple -- with armored cable, the box
    itself provides ground conductor continuity.  U.S. plastic
    boxes don't use metal cable clamps.

    The CEC is slightly different.  The CEC never permits cable
    armor as a grounding conductor.  However, you must still
    provide ground continuity for metallic sheath.  The CEC also
    requires grounding of any metal cable clamps on plastic boxes.

    The advantage of plastic boxes is comparatively minor even for
    non-metallic sheathed cable -- you can avoid making one ground
    connection and they sometimes cost a little less.  On the other
    hand, plastic boxes are more vulnerable to impacts.  For
    exposed or shop wiring, metal boxes are probably better.

Subject: Junction box positioning?

    A junction box is a box used only for connecting wires together.

    Junction boxes must be located in such a way that they're accessible
    later.  Ie: not buried under plaster.  Excessive use of junction
    boxes is often a sign of sloppy installation, and inspectors may
    get nasty.

Subject: Can I install a replacement light fixture?

    In general, one can replace fixtures freely, subject to a few
    caveats.  First, of course, one should check the amperage
    rating of the circuit.  If your heart is set on installing half
    a dozen 500 watt floodlights, you may need to run a new wire
    back to the panel box.  But there are some more subtle
    constraints as well.  For example, older house
    wiring doesn't have high-temperature insulation.  The excess
    heat generated by a ceiling-mounted lamp can and will cause the
    insulation to deteriorate and crack, with obvious bad results.
    Some newer fixtures are specifically marked for high
    temperature wire only.  (You may find, in fact, that your
    ceiling wiring already has this problem, in which case
    replacing any devices is a real adventure.)

    Other concerns include providing a suitable ground for some
    fluorescent fixtures, and making sure that the ceiling box and
    its mounting are strong enough to support the weight of a heavy
    chandelier or ceiling fan.  You may need to install a new box
    specifically listed for this purpose.  A 2x4 across the ceiling
    joists makes a good support.  Metal brackets are also available
    that can be fished into ceilings thru the junction box hole and
    mounted between the joists.

    There are special rules for recessed light fixtures such as
    "pot" lamps or heat lamps.  When these are installed in insulated
    ceilings, they can present a very substantial fire hazard.
    The CEC provides for the installation of pot lamps in insulated
    ceilings, provided that the fixture is boxed in a "coffin" (usually
    8'x16"x12" - made by making a pair of joists 12" high, and covering
    with plywood) that doesn't have any insulation.  (Yes, that's 8 *feet*
    long)

    NEC rules are somewhat less stringent.  They require at least 3"
    clearance between the fixture and any sort of thermal insulation.
    The rules also say that one should not obstruct free air movement,
    which means that a CEC-style ``coffin'' might be worthwhile.
    Presumably, that's up to the local inspector.  [The CEC doesn't
    actually mandate the coffin per-se, this seems to be an inspector
    requirement to make absolutely certain that the fixture can't get
    accidentally buried in insulation.  Ie: if you have insulation blown
    in later.]

    There are now fixtures that contain integral thermal cutouts and
    fairly large cases that can be buried directly in insulation.  They are
    usually limited to 75 watt bulbs, and are unfortunately, somewhat
    more expensive than the older types.  Before you use them, you should
    ensure that they have explicit UL or CSA approval for such uses.
    Follow the installation instructions carefully; the prescribed location
    for the sensor can vary.

    There does not yet appear to be a heat lamp fixture that is approved
    for use in insulation.  The "coffin" appears the only legal approach.

Subject: What does it mean when the lights brighten when a motor starts?

    This usually means that the neutral wire in the panel is
    loose.  Depending on the load balance, one hot wire may end up
    being more than 110V, and the other less than 110V, with
    respect to ground.  This is a very hazardous situation - it can
    destroy your electronic equipment, possibly start fires, and in
    some situations electrocute you (ie: some US jurisdictions
    require the stove frame connected to neutral).

    If this happens, contact your electrical authority immediately
    and have them come and check out the problem.

    Note: a brief (< 1 second) brightening is sometimes normal with
    lighting and motors on the same 220V with neutral circuit.  A
    loose main panel neutral will usually show increased brightness
    far longer than one second.  In case of doubt, get help.

Subject: What is 3 phase power?  Should I use it?  Can I get it in my house?

    Three phase power has three "hot" wires, 120 degrees out of
    phase with each other.  These are usually used for large motors
    because it is more "efficient", provides a bit more starting torque,
    and because the motors are simpler and hence cheaper.

    You're most likely to encounter a 3 phase circuit that shows
    110 volts between any hot and ground, and 208 volts between
    any two hots.  The latter shows the difference between a normal
    220V/110V common neutral circuit, which is 240 volts between the
    two hots.  There are 3 phase circuits with different voltages.

    Bringing in a 3 phase feed to your house is usually
    ridiculously expensive, or impossible.  If the equipment you
    want to run has a standard motor mount, it is *MUCH* cheaper to
    buy a new 110V or 220V motor for it.  In some cases it is
    possible to run 3 phase equipment on ordinary power if you have
    a "capacitor start" unit, or use a larger motor as a
    (auto-)generator.  These are tricky, but are a good solution if
    the motor is non-standard size, or too expensive or too big to
    replace.  The Taunton Press book ``The Small Shop'' has an
    article on how to do this if you must.

    Note that you lose any possible electrical efficiency by using
    such a converter.  The laws of thermodynamics guarantee that.

Subject: Is it better to run motors at 110 or 220?

    Theoretically, it doesn't make any difference.  However, there
    is a difference is the amount of power lost in the supply
    wiring.  All things being equal, a 220V motor will lose 4 times
    less power in the house wiring than a 110V motor.  This also
    means that the startup surge loss will be less, and the motor
    will get to speed quicker.  And in some circumstances, the
    smaller power loss will lead to longer motor life.

    This is usually irrelevant unless the supply wires are more
    than 50 feet long.

Subject: What is this nonsense about 3HP on 110V 15A circuits?

    It is a universal physical law that 1 HP is equal to 746
    watts.  Given heating loss, power factor and other inefficiencies,
    it is usually best to consider 1 HP is going to need 1000-1200
    watts.  A 110V 15A circuit can only deliver 1850 watts to a motor,
    so it cannot possibly be more than approximately 2 HP.  Given rational
    efficiency factors, 1.5HP is more like it.

    Some equipment manufacturers (Sears in particular, most router
    manufacturers in general ;-) advertise a HP rating that is far
    in excess of what is possible.  They are giving you a "stall
    horsepower" or similar.  That means the power is measured when
    the motor is just about to stop turning because of the load.
    What they don't mention is that if you kept it in that
    condition for more than a few seconds hopefully your breaker
    will trip, otherwise the motor will melt -- it's drawing far
    more current than it can continuously.

    When comparing motors, compare the continuous horsepower.  This
    should be on the motor nameplate.  If you can't find that figure,
    check the amperage rating, which is always present.

Subject: How do I convert two prong receptacles to three prong?

    Older homes frequently have two-prong receptacles instead
    of the more modern three.  These receptacles have no safety
    ground, and the cabling usually has no ground wire.  Neither
    the NEC or CEC permits installing new 2 prong receptacles anymore.

    There are several different approaches to solving this:
        1) If the wiring is done through conduit or BX, and the
           conduit is continuous back to the panel, you can connect
           the third prong of a new receptacle to the receptacle
           box.  NEC mainly - CEC frowns on this practise.
        2) If there is a copper cold water pipe going nearby, and
           it's continuous to the main house ground point, you can
           run a conductor to it from the third prong.
        3) Run a ground conductor back to the main panel.
        4) Easiest: install a GFCI receptacle.  The ground lug
           should not be connected to anything, but the GFCI
           protection itself will serve instead.  The GFCI
           will also protect downstream (possibly also two prong
           outlets).  If you do this to protect downstream outlets,
           the grounds must not be connected together.  Since it
           wouldn't be connected to a real ground, a wiring fault
           could energize the cases of 3 prong devices connected
           to other outlets.  Be sure, though, that there aren't
           indirect ground plug connections, such as via the sheath
           on BX cable.

    The CEC permits you to replace a two prong receptacle with a three
    prong if you fill the U ground with a non-conducting goop.
    Like caulking compound.  This is not permitted in the NEC.

Subject: Are you sure about GFCIs and ungrounded outlets?
    Should the test button work?

    We're sure about what the NEC and CEC say.  Remember, though,
    that your local codes may vary.  As for the TEST button -- there's
    a resistor connecting the LOAD side of the hot wire to the LINE
    side of the neutral wire when you press the TEST button.  Current
    through this resistor shows up as an imbalance, and trips the GFCI.
    This is a simple, passive, and reliable test, and doesn't require
    a real ground to work.  If your GFCI does not trip when you press
    the TEST button, it is very probably defective or miswired.  Again:
    if the test button doesn't work, something's broken, and potentially
    dangerous.  The problem should be corrected immediately.

    The instructions that come with some GFCIs specify that the ground
    wire must be connected.  We do not know why they say this.  The
    causes may be as mundane as an old instruction sheet, or with the
    formalities of UL or CSA listing -- perhaps the device was never
    tested without the ground wire being connected.  On the other hand,
    UL or CSA approval should only have been granted if the device
    behaves properly in *all* listed applications, including ungrounded
    outlet replacement.  (One of us called Leviton; their GFCIs are
    labeled for installation on grounded circuits only.  The technician
    was surprised to see that; he agreed that the NEC does not require
    it, and promised to investigate.)

Subject: How should I wire my shop?

    As with any other kind of wiring, you need enough power for all
    devices that will be on simultaneously.  The code specifies
    that you should stay under 80% of the nominal capacity of the
    circuit.  For typical home shop use, this means one circuit for
    the major power tools, and possibly one for a dust collector or
    shop vac.  Use at least 12 gauge wire -- many power tools have
    big motors, with a big start-up surge.  If you can, use 20 amp
    breakers (NEC), though CEC requires standard 20A receptacles
    which means you'd have to "replug" all your equipment.  Lights
    should either be on a circuit of their own -- and not shared
    with circuits in the rest of the house -- or be on at least two
    separate circuits.  The idea is that you want to avoid a
    situation where a blade is still spinning at several thousand
    RPM, while you're groping in the dark for the OFF switch.

    Do install lots of outlets.  It's easier to install them in the
    beginning, when you don't have to cut into an existing cable.
    It's useful if at least two circuits are accessible at each
    point, so you can run a shop vac or a compressor at the same
    time as the tool you really want.  But use metal boxes and
    plates, and maybe even metal-sheathed cable; you may have
    objects flying around at high speeds if something goes a bit
    wrong.

    Note that some jurisdictions have a "no horizontal wiring"
    rule in workshops or other unfinished areas that are used
    for working.  What this means is that all wiring must be
    run along structural members.  Ie: stapled to studs.

    Other possible shop circuits include heater circuits, 220V
    circuits for some large tools, and air compressor circuits.
    Don't overload circuits, and don't use extension cords if you
    can help it, unless they're rated for high currents.  (A coiled
    extension cord is not as safe as a straight length of wire of
    the same gauge.  Also, the insulation won't withstand as much
    heat, and heat dissipation is the critical issue.)

    If your shop is located at some remove from your main panel,
    you should probably install a subpanel, and derive your shop
    wiring from it.  If you have young children, you may want to
    equip this panel with a cut-off switch, and possibly a lock.
    If you want to install individual switches to ``safe''
    particular circuits, make sure you get ones rated high enough.
    For example, ordinary light switches are not safely able to
    handle the start-up surge generated by a table saw.  Buy
    ``horsepower-rated'' switches instead.

    Finally, note that most home shops are in garages or unfinished
    basements; hence the NEC requirements for GFCIs apply.  And
    even if you ``know'' that you'd never use one of your shop
    outlets to run a lawn mower, the next owner of your house might
    have a different idea.

    Note: Fine Woodworking magazine often carries articles on shop
    wiring.  April 1992 is one place to start.

Subject: Underground Wiring

    You will need to prepare a trench to specifications, use
    special wire, protect the wire with conduit or special plastic
    tubing and possibly lumber (don't use creosoted lumber, it rots
    thermoplastic insulation and acts as a catalyst in the corrosion
    of lead).  The transition from in-house to underground wire is
    generally via conduit.  All outdoor boxes must be specifically
    listed for the purpose, and contain the appropriate gaskets,
    fittings, etc.  If the location of the box is subject to immersion
    in water, a more serious style of water-proof box is needed.  And
    of course, don't forget the GFCIs.

    The required depths and other details vary from jurisdiction to
    jurisdiction, so we suggest you consult your inspector about
    your specific situation.

    A hint: buy a roll of bright yellow tape that says "buried power
    line" and bury it a few inches above where the wire has been placed.

Subject: Aluminum wiring

    During the 1970's, aluminum (instead of copper) wiring became
    quite popular and was extensively used.  Since that time,
    aluminum wiring has been implicated in a number of house fires,
    and most jurisdictions no longer permit it in new installations.
    We recommend, even if you're allowed to, that do not use it for new
    wiring.

    But don't panic if your house has aluminum wiring.  Aluminum
    wiring, when properly installed, can be just as safe as copper.
    Aluminum wiring is, however, very unforgiving of improper
    installation.  We will cover a bit of the theory behind potential
    problems, and what you can do to make your wiring safe.