Browse all questions

Disulfide bonds (S-S cross-links between two cysteine amino acids in adjacent keratin chains) are the strongest of the three side bonds in hair. Permanent chemical reshaping is the controlled breaking and reforming of disulfide bonds: a reducing agent such as ammonium thioglycolate or ammonium sulfite donates hydrogen to break the bond, the hair is reshaped on a rod or pressed straight, and an oxidizing neutralizer rebuilds the disulfides in the new position. Salt and hydrogen bonds are too weak to hold permanent shape. Peptide bonds are the backbone of the protein and are NOT broken in routine chemical services. The relevant SDS under Cal/OSHA §5194 spells out the hazards of both reducers and neutralizers.

Thioglycolate is a sulfur-containing reducing agent: it donates hydrogen to the disulfide bond, splitting it into two cysteine thiols, a reversible change that an oxidizing neutralizer can put back together. Sodium hydroxide is one of the strongest alkalis used on skin; at pH 12 to 14 it strips a sulfur atom out of the disulfide entirely, converting cystine to lanthionine, a permanent rearrangement that cannot be reversed and that is followed by a neutralizing (acidifying) shampoo rather than an oxidizer. The pH and mechanism differences explain why the two products MUST NOT be layered on the same hair without major breakage risk. SDS hazard information is required for both classes under Cal/OSHA §5194.

As bleach or high-lift color lifts natural pigment, eumelanin (the brown/black large-molecule pigment) breaks down first and pheomelanin (the smaller red/yellow molecule) lingers. Lifting therefore reveals predictable contributing pigments in a sequence: red (level 4), red-orange (level 5), orange (level 6), yellow-orange (level 7), yellow (level 8), pale yellow (level 9), and pale palest yellow (level 10). A level 8 lift typically shows yellow to yellow-orange and is toned with a violet or violet-blue toner to neutralize. California licensees apply oxidative color under CCR Title 16 §979.4. Options A, B, and D ignore the standard contributing-pigment chart taught in every cosmetology textbook.

Approximate rules of thumb taught for oxidative color: 10 volume is deposit-only with little to no lift; 20 volume lifts about 1 to 2 levels and is the workhorse for one-process gray coverage; 30 volume lifts about 2 to 3 levels; 40 volume lifts about 3 to 4 levels and is reserved for resistant hair and high-lift series. A 3-level lift from 6 to 9 is matched by 30 volume. Demi-permanent at 5 volume deposits only and will NOT lift to 9 (option C). 60 volume is not sold in California for cosmetic use (option D). Option A reverses the rule. California licensees apply oxidative color under CCR Title 16 §979.4.

The cuticle is made of overlapping keratin scales. In an alkaline environment (color, perm waving lotion, relaxer), the scales swell and lift, allowing larger molecules to penetrate to the cortex; this is necessary for chemical service to take effect. In an acidic environment (clarifying rinse, acid-balanced conditioner, finishing toner at low pH), the scales flatten and tighten against each other, sealing the cuticle, sealing in moisture, and increasing light reflection (shine). This is why an acidic conditioning rinse is used after an alkaline service. California licensees apply both kinds of products under CCR Title 16 §979.4. Options A, C, and D contradict basic cuticle chemistry.

Antibacterial agents target structures unique to bacterial cells. Antifungal agents target structures unique to fungal cells, most commonly ergosterol in the fungal cell membrane. The two classes act on different organisms and a product that kills bacteria is NOT automatically effective against fungi. California salon disinfectants used on non-porous, multi-use tools must be EPA-registered hospital-grade, which by definition means bactericidal, virucidal, and fungicidal (per CCR Title 16 §979.4 and BBC inspection practice). Many topical antifungals are OTC (clotrimazole, terbinafine). Options A, B, and C collapse or mis-state the categories.

Section 8 of an SDS lists occupational exposure limits, engineering controls, and recommended PPE. Sodium hydroxide is highly alkaline and corrosive to skin and eyes, so a relaxer SDS Section 8 will require chemical-resistant gloves (nitrile or similar), eye protection (safety glasses or face shield), and adequate ventilation, with engineering controls where feasible. The Cal/OSHA Hazard Communication Standard §5194 requires the salon to maintain and act on SDS information. Option A uses inappropriate gloves. Option B ignores PPE entirely and is a clear violation. Option D is wildly excessive and not what Section 8 calls for; PPE must be appropriate, not theatrical.

Once monomer has been dispensed into the dappen dish and used at the chair, it has picked up polymer powder, file dust, bacteria from the brush touching skin, and atmospheric moisture. Pouring it back into the stock bottle inoculates the entire bottle with contaminants and contaminates the next client's dish, and the trace polymer begins to thicken the supply. The professional practice is to discard the dappen dish contents, clean and dry the dish, and dispense fresh monomer for the next client. California licensees follow this under general sanitation duties at CCR Title 16 §979.4. Options A, B, and D state reasons that are not the actual sanitation rationale.

Direct current (DC) is a constant, one-directional flow of electrons. Galvanic devices use DC because chemical reactions such as iontophoresis and desincrustation depend on a steady polarity.

Standard United States wall outlets deliver alternating current (AC) at roughly 120 volts and 60 hertz. Salon equipment such as dryers and clippers is built to run on this AC supply.

Faradic current is an interrupted or pulsating alternating current. Its short pulses cause visible muscle contractions, which is why it has historically been used for facial muscle toning.

Like charges repel. An acidic, positively ionized product is pushed into the skin from the positive (anode) pole because the matching positive charge of the electrode repels the ions inward.

Desincrustation uses the negative pole (cathode) with an alkaline solution. The chemical reaction at the negative electrode saponifies (softens) sebum and oily debris, making deep cleansing easier.

High-frequency (Tesla) current is a rapidly oscillating AC. It generates small amounts of ozone and gentle heat at the glass electrode, which has a mild antiseptic and stimulating effect on the skin.

Microcurrent is extremely low-amperage current measured in millionths of an ampere. It is typically sub-sensory and is used for gentle stimulation of facial tissue, not for strong muscle contractions or tissue destruction.

Infrared radiation lies just beyond visible red light. Its wavelengths are absorbed as heat, gently warming the skin, dilating surface vessels, and helping product penetration. It is not germicidal.

Infrared lamps must be kept far enough from the skin to avoid burns. Manufacturer instructions and standard practice place the lamp roughly 18 to 30 inches from the treatment area, and the practitioner should always confirm the client feels gentle warmth, not pain.

Short-wavelength UV light has germicidal properties but causes eye injury and skin burns with even short exposure. UV cabinets are storage aids only and do not replace EPA-registered disinfectants for tools.

A GFCI compares current going out on the hot wire with current returning on the neutral. If even a small imbalance (around 5 milliamperes) flows to ground — for example, through a person standing in water — the device trips within milliseconds, sharply reducing the risk of electrocution.

Each circuit is rated for a maximum continuous load (often 15 or 20 amperes). Stacking high-draw appliances on one circuit through a power strip exceeds that rating, overheats the conductors, and is a common cause of electrical fires in salons.

A damaged cord can cause shock, burns, or fire. Industry safe practice and Cal/OSHA general electrical safety rules require removing damaged electrical equipment from service until properly repaired.

Grounding gives stray current a safe, low-resistance path to earth. If a wire inside the appliance contacts the metal case, the fault current trips the breaker through the ground wire rather than passing through the person holding the appliance.

Reusable tools that touch the client must be cleaned and then disinfected between clients. The manufacturer's directions specify the correct method and approved disinfectant for the electrode material.

California Board sanitation rules require non-electrical multiuse tools to be cleaned of visible debris and then disinfected by full immersion in an EPA-registered hospital disinfectant for the contact time on the label. UV cabinets are not disinfection.

California Board rules and manufacturer instructions require that electrical tools be cleared of debris and that the blades and other client-contact surfaces be disinfected with an EPA-registered disinfectant. The motor housing is never immersed in liquid.

California estheticians work on the superficial skin only. They may use non-medical galvanic, high-frequency, and microcurrent devices for facial care. Ablative lasers and needle electrolysis fall outside the esthetics scope of practice.

Electrical current from galvanic, high-frequency, and microcurrent devices can interfere with pacemakers and other implanted electronic medical devices, and is also generally contraindicated in pregnancy, epilepsy, and on broken skin. The client should be screened before treatment.

Water is an excellent conductor of electricity. Reaching into water that may be electrified can cause electrocution. The safe response is to remove the power source first — flip the circuit breaker or unplug the cord at the outlet — and only then handle the device.

Amperage equals watts divided by volts (Ohm's law applied to power: I = P/V). 1500 W divided by 120 V equals 12.5 A, which is very close to the 15 A breaker rating common in salon receptacles. Plugging a second high-wattage appliance into the same circuit will trip the breaker or, worse, overheat the wiring before the breaker trips, creating a fire risk behind the wall. California licensees are required under CCR Title 16 §979 to maintain equipment in safe working order and to follow manufacturer load instructions. Option C and D undercount the math. Option A confuses watts with amps and is off by an order of magnitude.

A conductor is a material through which electric current flows readily; an insulator resists current flow. Copper wiring carries current in tools; water and the moist human body conduct electricity, which is exactly why GFCI protection is required where water and electricity meet. Rubber, dry wood, glass, and silk insulate, which is why tool handles are rubber and the technician should stand on a dry floor. California regulates safe equipment use under CCR Title 16 §979.2. Option B reverses the categories. Option A is the opposite of physical reality. Option C treats conductivity as binary; it is a continuum and copper is the practical workhorse conductor.

A ground-fault circuit interrupter continuously compares the current leaving on the hot wire with the current returning on the neutral wire. In a healthy circuit they are equal. When even a few milliamps (typically 4 to 6 mA) of current leaks elsewhere, for example through a person standing in water, the GFCI senses the imbalance and trips within milliseconds, well before the current is sufficient to stop a heart. California requires GFCI protection at receptacles near water sources, consistent with CCR Title 16 §979.2 and the National Electrical Code. The other options describe measurements the GFCI does not perform.

A plug that becomes very hot indicates a poor electrical connection, frayed wiring, or a damaged outlet, any of which is a fire hazard. The professional response is to tag the device out of service and remove it from use until it is repaired by a qualified person or replaced. California licensees are required under CCR Title 16 §979.2 to maintain equipment in safe operating condition. Option C continues the hazard. Option D introduces water near electricity and creates an immediate shock risk. Option B masks the symptom and accelerates the failure, possibly arcing inside the wall.

Pulling on the cord rather than the plug stresses the wire-to-prong solder joints inside the plug, eventually loosening them. Loose internal connections create arcing, overheating, and the kind of brittle, cracked plug that ignites lint. The correct technique is to grasp the molded plug body and pull straight out, perpendicular to the wall. California licensees are required to keep equipment in safe condition under CCR Title 16 §979.2, and cord care is part of that duty. Option D guarantees cord damage. Option C wrenches the prongs and damages the outlet. Option B leaves the device energized at the cord and plug, which is unsafe storage.

High-frequency current uses an oscillating alternating current that produces a small electromagnetic field at the electrode. That field can interfere with implanted cardiac pacemakers and other electronic medical devices, so a pacemaker is an absolute contraindication for high-frequency, galvanic, and microcurrent services. California estheticians performing electrotherapy must screen for this on the consultation form, consistent with the safe-equipment-use duties of CCR Title 16 §979.2. Pregnancy, metal implants in the treatment area, epilepsy, and severe heart disease are additional contraindications. Options A, B, and C are not contraindications; they describe ordinary client conditions.

Microcurrent, as its name suggests, is delivered in MICROamperes, on the order of millionths of an ampere. The level is so low that most clients feel only a faint metallic taste from electrodes near the mouth, not muscle contraction. The current is thought to influence the resting bioelectrical state of facial tissue without forcing visible contractions, in contrast to faradic current, which deliberately contracts muscle. California electrotherapy use sits under CCR Title 16 §979.2 and the BBC's scope rules. Option B confuses microcurrent with faradic. Option C confuses it with high-frequency. Option A is physically impossible and is not a real device specification.

Facial steamers heat water and draw substantial current; LED panels typically draw less but still add to the load. Combining them on one circuit, especially via a daisy-chained power strip, risks tripping the breaker or overheating the wiring. The safe practice is to plug them into separate circuits, and the wet-area device must be GFCI-protected per California salon electrical practice referenced under CCR Title 16 §979.2 and the National Electrical Code adopted by reference. Option A creates a fire risk and is explicitly discouraged by manufacturers. Option B minimizes the actual steamer load. Option D is the opposite of safety practice; grounding is required, not optional.

The power equation states that power in watts equals voltage in volts multiplied by current in amperes, so W = V x A. This is why a 1500 W appliance on a 120 V circuit draws 12.5 A, and why the same 1500 W on a 240 V circuit would draw only 6.25 A. Understanding the formula prevents overloaded circuits in the salon, an issue addressed by safe equipment use under CCR Title 16 §979.2. Option C and D rearrange the variables incorrectly. Option B divides where multiplication is required and is the formula that fails on every electrical exam item.

A 1500 W flat iron on a 120 V circuit draws roughly 12.5 A, putting a 13 A extension cord right at its limit; small additional resistance in the connectors will push current past the cord rating, heating the cord. Extension cords are not intended for permanent salon use with high-wattage heat appliances, and California licensees must keep equipment safe per CCR Title 16 §979.2. The right answer is to plug the iron directly into a properly rated wall outlet. Tightly coiling holds in heat and accelerates insulation breakdown. Running cord under a rug hides damage and traps heat. Bundling multiple appliances on one cord multiplies the load and is a common cause of salon fires.

The standard intake screen for electrotherapy lists implanted electronic medical devices (pacemakers, ICDs, neurostimulators) as absolute contraindications because the device may be disrupted by the salon device's electromagnetic field. Pregnancy is generally contraindicated for galvanic current (iontophoresis is poorly studied in pregnancy) and microcurrent. Metal implants in the treatment area concentrate current. Epilepsy and severe heart disease are also screened out. California licensees must comply with safe equipment use under CCR Title 16 §979.2 and screen for these factors before energizing any client. Options A, B, and D are not medical contraindications and reflect ordinary client activities or characteristics.

Apply I = P / V (Ohm's-law power form). 1875 W / 120 V = 15.6 A, which is at or above a typical 15 A salon breaker rating; this means a salon hair dryer alone effectively saturates one circuit and should NOT share that circuit with another heat appliance. The 60 W flat iron draws 0.5 A and the 90 W curling iron draws 0.75 A. The dryer is by far the largest electrical load in the salon and is the single most common cause of nuisance breaker trips and cord overheating. California safe-equipment-use is at CCR Title 16 §979.2. Options A, B, and C contradict the basic math.

Small consumer/professional devices often need a much lower voltage (5, 9, 12, 24 V DC) than the 120 V AC that comes out of the wall. The 'wall-wart' or in-line block contains a small step-DOWN transformer plus rectifier and filter circuitry that converts the 120 V AC down to the device's required low voltage DC. The transformer also provides galvanic isolation between the household mains and the user-facing low-voltage side, which improves safety. It does NOT replace a GFCI (option D), step voltage up (option A), or do anything to the air (option B). Equipment safety is required under CCR Title 16 §979.2.

Water and the wet human body are both conductors. If an energized appliance falls into a shampoo bowl or pedicure tub, or if a person touches an energized component while standing in water, a current path opens through the person to ground. A GFCI continuously compares the current on the hot wire to the current returning on the neutral wire; an imbalance of just a few milliamps (4 to 6 mA) signals leakage to ground (a person) and trips the receptacle in milliseconds, well before the current is sufficient to stop a heart. This is why the National Electrical Code and California salon practice require GFCI protection within roughly 6 feet of water sources, consistent with CCR Title 16 §979.2 safe-equipment-use duties.

California regulation requires multi-use implements be totally immersed in an EPA-registered disinfectant for at least 10 minutes (or the time specified on the product label, if longer).

Salons must disinfect multi-use tools using an EPA-registered hospital-grade product. Sterilization (which kills spores) is not required for salon practice, and sanitization alone is not sufficient between clients.

California requires the disinfectant to be EPA-registered and labeled as bactericidal, virucidal, and fungicidal. Sporicidal activity is not required for salon disinfection.

Emery boards are porous and cannot be properly disinfected, so they are single-use and must be discarded after one client. Metal nippers, shears, and plastic clipper guards are non-porous and can be disinfected for reuse.

Methyl methacrylate (MMA) is prohibited on natural nails in California because of its dangerously strong bond and respiratory sensitization. Ethyl methacrylate (EMA) is the legal substitute.

California prohibits double-dipping. Once an applicator touches the client's skin, it cannot return to the wax pot. Use a fresh stick or apply with a method that prevents re-contact. Reheating wax does not decontaminate it.

Under Cal/OSHA Bloodborne Pathogen Standard 8 CCR §5193, the first action is to stop the service and don disposable gloves before any contact with blood. Direct application of styptic from the bottle is prohibited (no single-use applicator).

California regulation requires the licensee to refuse service when a contagious or infectious condition (such as active fungal infection) is present, and to refer the client to a physician. Performing the service would risk exposure to staff, equipment, and the next client.